@Galle:
Here, I'll define one fallacy for him...
Appeal to consequences: An argument for or against a premise on the grounds of whether the premise leads to desirable or undesirable consequences. As such it does not address the validity of the premise at all, but attempts to decide whether it is true or false from whether it ought to be true or false. Hence an appeal to consequences is the reverse of the naturalistic fallacy ('ought' from 'is') and a category error.
E.g. "Atheism must be wrong, otherwise all your loved ones couldn't go to heaven!"
Another, indirect, appeal to consequences would be to argue for or against something on the grounds of how it might affect people with similar views. Again, the validity of the item/concept under consideration is treated as subordinate to a facile treatment of the possible outcomes.
E.g. "Don't say things like that, it makes the rest of us look bad!"
It is interesting that as well as a "council of perfection" (i.e. expecting, in this case, everyone to behave with perfect propriety in order to deflect criticism) Regolith is undermining other atheists' arguments to the effect that atheism isn't a religion, since he implies collectivism and organisation amongst atheists. A valid response to someone pointing out an atheist behaving irrationally would be to say "He's got his views, I've got mine. It's not like we're members of the same church or anything.". If done in a debate, point out that this is the fallacy of 'guilt by association' and ask that they address your points directly.
@Regolith:
Everybody here is (almost certainly) human, so criticising people for behaving like it is unrealistic. To argue that as atheists, they should be held to some 'higher standard' of behaviour is just elitist and snobbery. Atheists come in all shapes, sizes, colours, persuasions and levels of ability. If you find a stupid one, I suggest you do what we do, point and laugh!
It's not terribly constructive, but it's fun!