i’ve already mentioned some mash-ups, here comes one more, not exactly a mash-up, but a band that mixes metallica and beatles songs: beatallica. all 11 songs can be conveniently downloaded as a torrent-file or as single .mp3-downloads. get them while they last.
oh, and just to make this post more complete (or actually post a real mash-up), did i ever mention the beastles? an excellent mash-up between the beatles and the beastie boys.