Almost every sketch in the show is a winner, and the cherry on top is that unlike other sketch shows of the time, over time plenty of the characters actually grow and change (I'm thinking specifically of the storyline that develops between Ted and Ralph, which is of such high writing quality that it could easily have been it's own series). Other classic skits include Jazz Club (nice) where the presenter slowly grows disillusioned with the music on his show, Unlucky Alf, who's luck decreases exponentially as the show progresses and of course The Off-roaders, which is just brilliant satire. There are a few weak characters imo (I never found Swiss Toni or the Suit You Sir guys to be very funny, despite the fact that they were the most popular characters). Regardless, it's a milestone in TV comedy and, while maybe not remembered very well, has obviously influenced plenty of modern comedies. Highly recommended.
Review of The Fast Show
