wow, this has to be the most brain racking question, it involves going through memories upon memories of my brain hurts now you bastard...
and yet I still sit here thinking..... ggggeeeezzzzz ..
um....some of the funniest parts are all skits from 20 minutes of setting the joke up piece by piece so that the conclusion is just deeper than you can imagine, eg with the episode of peep show and mummy, each joke lands them deeper and deeper until you're left wondering what and where could they possibly go next and that's why I believe the peep show is the best comedy ever written thanks to it's brutal honesty.
but, a 1 liner or a 2 liner which has it's own merit, sit coms don't do it with the exception to family guy where it can go it's own entire joke, because the jokes are in your face, 0-1% thinking time required to watch family, it's just punchline after punchline of really quite terrible jokes, but that aside (american dad is better... whistles) ...
even the funniest memories of panel shows, you'll find 9/10 it's the same re-used joke on someone they don't 'like' .... until eventually the other one bites and it's ooooOOOOOOoooooo and people are at home cracking up over the childnish level but with nicely injected wit and political view, never mind the buzzcock to the same extent minus the wit.
so it's difficult, which leads me stand ups...
So Jimmy Carr it has to be because he's the current champ for 1 liner's.
just jump to (3:29/7:53)
Is my favourite set of gags from him, tell me you don't laugh once, esp the birthday gift - lol cracking up just thinking about that set.