This is an old one, but it still makes me laugh.
According to Wikipedia; Calhoun Tubbs David Alan Grier portrays an old bluesman whose songs invariably insult or otherwise offend his audience. Catchphrase: "Wrote a song about it. Like to hear it? Here it go!" "Thank you very much!" His catchphrase was also used as the intro to En Vogue's "Free Your Mind". He also always strums the same bar of blues and ends his little songs with "Ahhhhahaha"