In 4.5 weeks it’ll be the London Mini Maker Faire at Elephant and Castle. You can still get tickets and take a look at some of the cool stuff that is likely to be there.
Last year was the first year that this event ran and it was really good, so I can thoroughly recommend it to you.
I’m going to be there myself for at least part of the day even though it does clash with day two of the Music Production Expo.
Anyway, full details plus tickets etc here.