Heaneyland!

They did the mash

I like my mash-ups pretty well, but if you want to hear some of the best examples of the genre, go here. He's been keeping most of his tracks offline, but the most-requested mixes have been re-posted, and will be available until the 5th. I particularly recommend "Ray of Gob" (Madonna vs. the Sex Pistols) and "I Wanna Dance With Some Bono" (Whitney Houston vs. U2).