Police Squad was a 30-minute parody of cop shows (M Squad seems to have been a particular target) put together by the guys who did Airplane! Like that movie, it's full of sight gags and rapid-fire jokes, some of which hit and some of which miss. It lasted only 6 episodes, but it inspired the Naked Gun movies, which were pretty successful. Leslie Nielsen was the star of both the movies and the TV series.
A lot of the bits on the TV series make me laugh: the shine boy who has all the tips (and can even explain psychology to Dr. Joyce Brothers), the guest stars who get killed off in the opening sequence each week, the really dumb stuff like a tow truck shaped like a toe, and so on. The parody material works well, too, at least most of the time. I doubt that you'd want to watch all 6 shows in a row, but taken one at a time they're pretty funny stuff. If you've never seen the show, check it out.