I saw Sigur Rós at Coachella and WOW they are just that good. I'm listening to their album Ágætis Byrjun and it's like U2's Joshua Tree. You might be able to find their mp3s on Google.

Update: On an even stranger note, Zach Slow is trying to get random with Lady Sovereign who he saw play at Coachella. Check out the videos, especially of Jelly Doghnut.