John Doran (TheQuietus editor) playing DJ in an open air car park just off Old Street. Wed evening, 16 July. I think it's free but not sure.

http://thequietus.com/articles/15674-red-market-subject-wednesdays-dj-programme 

https://www.facebook.com/events/298139427021855/
http://www.subjectyourself.co.uk/
http://www.redgallerylondon.com/