I was bored today and googled for "funny fugue". Found a bunch of hilarious fugues on silly subjects like Mary Had a Little Lamb, Happy Birthday, etc.. Most of them were amateurish / sophomorish, however, and not really convincing musically. But I did run into a couple that are pretty convincing musically:
Nokia-Fuge by Christoph Berner, based on the infamous Nokia ringtone. Hilariously melodramatic, but can stand on its own as a piece of music.
"Funny Fugue" by Vladimir Shainsky, for children's choir. This one is actually quite seriously composed, in spite of the title, and sounds really good.
What other funny fugues do you know of that are able to stand on their own as genuine pieces of music?
Edit: This one isn't written to be a funny fugue; it's Bach's Contrapunctus I from The Art of Fugue, but played on ... beer bottles... The facial expressions are just ... priceless...