last.fm – Chart to M3U Playlist Generator:
http://lastm3u.powha.net/
chart/graph your music taste:
http://lastgraph.aeracode.org/
Fetch your Last.fm data, munge it and then do wonderful things:
http://l.alanedwardes.com/my/
Visualise Last.fm’s network of similar artists and bands:
http://pattie.fe.up.pt/i_know_that_artist/
do you know one where you can post bands you’ve seen live? I’ve been looking for one for a while…