Particularly in continental Europe, but farther afield too.. I'm aware that for many the UK is abroad, but no UK festivals allowed. There seem to be so many now, with good lineups, and in places I would like to go.
Two I've stumbled across recently are http://www.flowfestival.com/ in Helskinki, which looks great if a little 'spenny.
..and http://www.plisskenfestival.gr/ in Athens. Two days but well cheapz, and another good lineup.
Basically I want more ideas for this summer.. Hit me