Cabin Pressure is absolutely brilliant. Agree with everyone here.
John Finnemore has written some great stuff. Try John Finnemore’s Souvenir Programme for some more standard sketch comedy. He also is a regular contributor to many of the satirical news programs on the radio (he sometimes appears on The Now Show).
You can also find on Youtube a voice-over of Arthur explaining the rules of Yellow Car (you are always playing Yellow Car).
And agree with Boulter about Old Harry’s Game.