Jimmy Carr, who we've linked to a couple of times before, is a very funny guy. He's the host of 8 Out of 10 Cats, a most excellent panel show in the UK, as well as the annual Big Fat Quiz. He is extraordinarily quick. If you sit down front at one of his shows, there's no telling what might happen. Just try not to get noticed.
Warning: the vids are a bit blue. So if you're easily offended then...um, do you know what site this is...? You might try this instead.
And for the love of all that's holy, don't try to beat him at his own game. Because this sort of thing is Jimmy's bread and butter. Check this out (aspect ratio's all wonky, but it's short).