I'd like to second the multiple venues per event request: for multi-venue/multi-stage events it'd be handy to be able to record the venue/stage per band.
Additionally, especially for multi-day events, it would be useful to be able to (optionally) store the day and time each band plays. This could turn last.fm into a good 'festival guide'.
(I ran into this when considering adding the 'Nijmeegse Vierdaagsefeesten': a free 7-day event with something like 120 bands performing all over town. Adding them as one big flat list just doesn't make much sense)
If this gets implemented, I'd be interested in contributing a web mashup that festival organizers could use: organizers would add their festival lineup to last.fm and the mashup would generate some programme/timetable/artist pages for easy integration into their own sites automatically.
Such a tool might draw both organizers and new listeners to last.fm .
Technically, it might be nice to use iCalender/xCalendar as an intermediate format to further open up the information on both sides.
Actually, it would make sense for "festival" to be a sort of grouping of events, rather than simply an event with a title other than the names of the bands.
Tours could be another type of event grouping. A tour could have its own title, and contain events over a range of dates and venues, sharing one or more artists (although they should allow other additional artists, to account for partial tour partners and opening acts).
