STP covering Pearl Jam
Placebo - Running Up that HillPlacebo - Johnny and MaryPlacebo - Daddy Cool
Alarm Will Sound - Acoustica (Orchestra remixes of Aphex Twin - Drukqs)
A couple of my favorite funny ones...
tori amos covering nirvana (video is lame but song is actually really good)
jesse lacey (brand new) covering neutral milk hotel
nirvana covering leadbelly