Pretty much everything worth watching since Python owes a lot to it;
having said that, some of their sketches were fairly mediocre, especially, in my opinion, the hallowed Parrot Sketch.

Just watched a DVD of the Armando Iannucci Shows this week. That's pretty good too, if it can properly be considered a sketch show. Or otherwise.
( Moon Girl Technologies horrendous beanbag, Sun 17 May 2009, 17:05, archived)