What's the funniest song you ever heard?

Zappa's "We gotta stick together", "Catholic girls",

I agree with Frank Zappa (adding "please don't eat the Yellow Snow"), Randy Newman (adding "Short People") and various Dr. Hook. I'd also add Warren Zevon (e.g. "Werewolves of London") and Tonio K (e.g. "Life in the Foodchain", "H-A-T-E-R-E-D").

Tom Lehrer's "That was the week that was" album - every song is a hoot, though my particular favourites are "New Math", "The Vatican Rag", and "Pollution". Also, try to check out the "Stairways To Heaven" album. Eleven different versions of "Stairway To Heaven", my favouite is the Australian country version.

"Didn't You Kill My Brother" by Alexei Sale is also pretty funny in a twisted sort of way, as is "Cousin Dupree" by Steely Dan.

Pretty much anything by Blowfly.

You have to hear Patrick Sky - Songs That Made America Famous. Recorded in 1973 with a warning on the back: Despite redeeming social importance, this album should be approached with caution.

Offensive and sick/funny songs like:
1. Ramblin' Hunchback
2. Bake Dat Chicken Pie
3. Rock Star
4. Yonkers Girl

Type his name in Google and you can see he recorded a number of folk albums before coming totally off the wall with this. Funny for those not easily offended.