Maybe an obvious choice, but the Barbican is always good. My favourite space in there is the curve gallery, last time I went was for Cory Arcangel's 'Beat the Champ'. I love the architecture, although not many people do. I think it was voted 'London's ugliest building' in 2003.
Beautiful, calm location for lunch on a sunny day in London. Housed in a former school bike shed on Arnold Circus in Shoreditch. Great seasonal fresh food.
Brilliant Corners...Great sound system, vinyl only, dancing, left field, fourth world, jazz, afro, and some refreshing cocktails to help with all the sweating. Probably the only place i will actually dance in.
They also do amazing Japanese food earlier in the evening.