The annual orgy of free music returns to the Roundhouse in Camden. Highlights include series opener Lady Gaga (1), Sigur Rós (2), Arctic Monkeys (9), Kings of Leon (11), Primal Scream (20), Pixies (25) and Justin Timberlake (29). Register on the iTunes website then cross your fingers you get lucky and win tickets.

Sep 1-29. 7pm  FREE  
The Roundhouse Chalk Farm Road, NW1 8EH 
Tube | Chalk Farm 

Photo: Getty