Thanks for mentioning Songkick, I just registered there and looks like a good service overall. Reminds me of some of the last.fm functionality I was using in the past for that matter. What its still missing, is support for the functionality I described for festivals. Yes, they match festivals for you, but they don't tell you, which bands you should see there. Also they would have to update their database pretty often to i.e. work for Fusion festival, which announces the line-up only a few days prior to the festival, or to account for additions to/changes in festival line-ups.