"Taxi" is another of my favorite sitcoms of all-time, and is generally overlooked in the discussion of the best in TV history. It had a memorable cast of characters and the show was still going strong when it left the air in 1983.
I had a number of favorite episodes, but one of the funniest was one called "Art Work," when the cab drivers get together and pool their money to try to buy a painting of an artist who is about to die. It includes a number of hysterical Louie DePalma moments, one of my favorite sitcoms characters.
This clip is from the middle of the show, when the art auction takes place. It's number 21 on the countdown. Enjoy.