Here’s a great list for your debating toolkit. Some of the examples given could use refinement, but it’s still a handy reference.

I’ve pinched these definitions from the research doc for an infographic on Information is Beautiful. Even more interesting is the identification of these fallacies employed in Cardinal Keith O’Briens disgusting ‘tyranny of tolerance’ Telegraph article.

List of rhetological fallacies

Ad hominem

Bypassing the argument by launching an irrelevant attack on the person and not their claim.
Anyone that says we should build the Ground Zero Mosque is an American-hating liberal.

Affirming the consequent

Assuming there’s only one explanation for the observation you’re making.
Marriage often results in the birth of children. So that’s the reason why it exists.

Anecdotal evidence

Discounting evidence arrived at by systematic search or testing in favor of a few firsthand stories.
I’m going to carry on smoking. My grandfather smoked 40 a day until he died aged 90.

Appeal to (questionable) authority

Claiming something is true because an (unqualified or untrustworthy) ‘expert’ says it is.
Over 400 prominent scientists and engineers dispute global warming.

Appeal to common practice

Claiming something is true because it’s commonly practiced.
This bank has some problems with corruption. But there’s nothing going on here that doesn’t go on in all the other banks.

Appeal to consequences of a belief

Arguing a belief is false because it implies something you’d rather not believe.
That can’t be the Senator on that sextape. If it were, he’d be lying about not knowing her. And he’s not the kind of man who would lie.

Appeal to fear

An argument is made by increasing fear and prejudice towards the opposing side.
Before you know it there will be more mosques than churches.

Appeal to flattery

Using an irrelevant compliment to slip in an unfounded claim which is accepted along with the compliment
Intelligent and sophisticated readers will of course recognise a fallacy like this when they read one.

Appeal to ignorance

A claim is true simply because it has not been proven false (or false because it has not been proven true.)
Nobody has proved to me there is a God. So I know there is no God.

Appeal to money

Supposing that, if someone is rich or something is expensive, then it affects the truth of the claim.
If it costs more, it must be better.

Appeal to novelty

Supposing something is better because it is new or newer.
Awesome! The latest version of this operating system is going to make my computer faster and better…

Appeal to pity

Attempt to induce pity to sway opponents.
The former dictator is an old, dying man. It’s wrong to make him stand trial for these alleged offenses.

Appeal to popular belief

Claiming something is true because the majority of people believe it.
Milk is essential for healthier bones.

Appeal to probability

Assuming because something could happen, it will inevitably happen.
There are billions of galaxies with billions of stars in the universe. So there must be another planet with intelligent life on it.

Appeal to ridicule

Presenting the opponent’s argument in a way that makes it appear absurd.
Faith in God is like believing in Santa Claus and the Tooth Fairy.

Appeal to tradition

Claiming something is true because it’s (apparently) always been that way.
Marriage is the union between man and women. Therefore gay marriage is wrong.

Appeal to wishful thinking

Suggesting a claim is true or false just because you strongly hope it is.
The President wouldn’t lie. He’s our leader and a good American.

Biased generalising

Generalising from an unrepresentative sample to increase the strength of your argument.
Our website poll found that 90% of internet users oppose online piracy laws.

Burden of proof

I don’t need to prove my claim – you must prove it is false.
I maintain long-term solar cycles are the cause of global warming. Show me I’m wrong.

Circular logic

A conclusion is derived from premises based on the conclusion.
Stripping privacy rights only matters to those with something to hide. You must have something to hide if you oppose privacy protection.

Circumstance ad hominem

Stating a claim isn’t credible only because of the advocate’s interest in their claim.
A study into the health risks of mobile phone involved mobile phone companies. Therefore, the study cannot be trusted.

Composition

Assuming that characteristics or beliefs of some or all of a group applies to the entire group.
Recent terrorist attacks have been carried out by Islamic groups. Therefore all terrorists are muslims.

Denying the antecedent

There isn’t only one explanation for an outcome. So it’s false to assume the cause based on the effect.
If you get a degree, you’ll get a good job. If you don’t get a degree, you won’t get a good job.

Division

Assuming that characteristics or beliefs of a group automatically apply to any individual member.
Many Conservatives wish to ban gay marriage, discredit climate change, and deny evolution. Therefore all conservatives are homophobic, anti-environment creationists.

False dilemma

Presenting two opposing options as the only two options while hiding alternatives.
We’re going to have to cut the education budget or go deeper into debt. We can’t afford to go deeper into debt. So we’ll have to cut the education budget.

Gambler’s fallacy

Assuming the history of outcomes will affect future outcomes.
I’ve flipped a coin 10 times in a row and it’s been heads, therefore the next coin flip is more likely to come up tails.

Genetic fallacy

Attacking the cause or origin of a claim, rather than its substance.
Of course, mainstream liberal media aren’t going to say Barack Obama is a Muslim.

Middle ground

Assuming because two opposing arguments have merit, the answer must lie somewhere between them.
I rear ended your car but I don’t think I should pay for the damage. You think I should pay for all the damage. A fair compromise would be to split the bill in half.

Post hoc ergo propter hoc

Claiming that because one event followed another, it was also caused by it.
Since the election of the President more people than ever are unemployed. Therefore the President has damaged the economy.

Red herring

Introducing irrelevant material to the argument to distract and lead towards a different conclusion.
Why should the senator account for irregularities in his expenses? After all, there are senators who have done far worse things.

Slippery slope

Assuming a relatively small first step will inevitably lead to a chain of related (negative) events.
If we legalize marijuana, more people will start using crack and heroin. Then we’d have to legalize those too.

Special pleading

Universal principles do not apply to me or my argument.
No one is above the law. But I wouldn’t rat on anybody.

Spotlight

Assuming an observation from a small sample size applies to an entire group.
This large shoe manufacturer employs children in sweatshops. Therefore all shoe companies are evil child-slave owners!

Straw man

Creating a distorted or simplified caricature of your opponents argument, and then arguing against that.
You say Israel should stop building settlements on the West Bank in violation of treaty. So you’re saying Israel doesn’t have the right to be a nation?

Two wrongs make a right

Assuming that if one wrong is committed, another wrong will cancel it out.
Sure – the conditions in this prison are cruel and dehumanising. But these inmates are criminals!

Undistributed middle

Assuming because two things share a property, that makes them the same thing.
A theory can mean an unproven idea. Scientists use the term evolutionary theory. Therefore evolution is an unproven idea.

Appeal to anonymous authority

Using evidence from an unnamed ‘expert’ or ‘study’ or generalised group (like ‘scientists’) to claim something is true.
They say that it takes 7 years to digest chewing gum.

Appeal to incredulity

Because a claim sounds unbelievable, it must not be true.
The eye is an incredibly complex biomechanical machine with thousands of interlocking parts. How could that exist without an intelligent designer?

Appeal to nature

Making your claim seem more true by drawing a comparison with the “good” natural world.
Of course homosexuality is unnatural. You don’t same-sex animals copulating.

Begging the question

Making a claim while leaving out one or more major contributing factors that may affect the conclusion.
If we label food with warning labels, it will encourage people to eat more healthily.

Cum hoc ergo propter hoc

Claiming two events that occur together must have a cause-and-effect relationship. (Correlation = cause).
Teenagers in gangs listen to rap music with violent themes. Rap music inspires violence in teenagers.

Relativist fallacy

Rejecting a claim because of a belief that truth is relative to a person or group.
That’s perhaps true for you. But it’s not true for me.

Unfalsifiability

Offering a claim that cannot be proven false, because there is no way to check if it is false or not.
He lied because he’s possessed by demons.

Appeal to spite

Dismissing a claim by appealing to personal bias against the claimant.
Don’t you just hate how those rich Liberal Hollywood actors go on TV to promote their agendas?

Confirmation bias

Only looking only for evidence that supports your idea while ignoring contradicting evidence.
It’s obvious 9-11 was a American-government led conspiracy to justify war in Iraq and Afghanistan. No plane hit the Pentagon. The Twin Towers collapse was a controlled demolition… etc.

Guilt by association

Discrediting an idea or claim by associating it with an undesirable person or group.
Oh you want to relax the anti-terrorism laws just like the terrorists want us to do. Are you saying you support terrorism?

Hasty generalisation

Drawing a general conclusion from a tiny sample.
I just got cut up by the woman driver in front. Women can’t drive.

Ignoring a common cause

Claiming one event must have caused the other when a third (unlooked for) event is probably the cause
We had the 60s sexual revolution, and now people are dying of AIDS.

Lie

An outright untruth repeated knowingly as a fact.
“I did not have sexual relations with that woman.”

Misleading vividness

Describing an occurrence in vivid detail, even if it is a rare occurrence, to convince someone that it is a problem.
After legalising gay marriage, school libraries were required to stock same-sex literature; primary schoolchildren were given homosexual fairy stories and even manuals of explicit homosexual advocacy.

Perfectionist fallacy

Assuming that the only option on the table is perfect success, then rejecting anything that will not work perfectly.
What’s the point of these anti-drunk driving ad campaigns? People are still going to drink and drive no matter what.

Suppressed evidence

Intentionally failing to use significant and relevant information which counts against one’s own conclusion.
This Iraqi regime possesses and produces chemical and biological weapons. It is seeking nuclear weapons.

Ad hoc rescue

Trying to save a cherished belief by repeatedly revising the argument to explain away problems.
But apart from better sanitation, medicine, education, irrigation, public health, roads, a freshwater system and public order… What have the Romans done for us?

Jumping to conclusions

Drawing a quick conclusion without fairly considering relevant (and easily available) evidence.
She wants birth control in her medical cover — what a slut!

Sweeping generalisation

Applying a general rule too broadly.
Those young men rioted because they lacked morally responsible fathers.

Perhaps these could be turned into more journalism warning labels.

Original infographics

Updated to add this tweet from Martyn Kelly:

And see Wikipedia’s own list of fallacies.