This tool has been knocked up by Christopher Gutteridge, firstname.lastname@example.org , @cgutteridge, to demonstrate the cool stuff you can do when data is made open. It's hosted by the University of Southampton and is provided without any promise of reliability in the hope people will find it useful.
See the footer for the list of data sources.
This site uses Linked Open Data, which basically means it mashes up data from the festival timetable and dbpedia. The links are done via joining stuff up using the 'homepage' address as a way to join up the two datasets. This only works for the bands which had a homepage listed, and is a bit flakey as it'll match bands, artists, albums and tours in wikipedia, but I figure that we can safely pull out related cities and genres, at least well enough to be interesting.
Think you can do better? Great! Help yourself to the data! Please respect the licenses. Let me know if you do something amazing.
Clashfinder General provide an awesome site for deciding what to watch, and printing out the listings.