A friend of mine does a song called "The Alcohol of Fame" whenever a drunk gets too obnoxious. I don't know if it's in the db, but it's a great one.
2nds on Seamus Kennedy's "Old MacDonald's Deformed Farm." VERY un-pc, but brings tears of mirth to your eyes. I once played it for friends as we drove down I-95 and we actually had to pull over, lest we run off the road, we were laughing so hard.
I am never allowed to leave a campfire these days without playing Dan Bern's "Jerusalem". It doesn't SEEM funny, but there's a section that I can't get through without finally breaking down in laughter...