UK travel

I almost titled this London Calling, but a decade of bad travel writing and lame headlines stayed my hand. In 41 days, I will be flying to the UK for four nights in London, before boarding a small plane headed for my new Central European home. So, I'm soliciting ideas of things to do while there. Accomodations are sorted, and I already know that I will be taking in a Chelsea match on the Saturday (I'll be in town Thursday until Monday morning), walking over that pedestrian bridge and having tea and scones in the crypt of some church (right, Jess?). I will do some of the "must see" tourist things, but I like off the wall and bizarre things too.

Any suggestions?