The Cheerson CX-10 is quite a cool little quadcopter. When I say little, it really is tiny, about 1.5″ across. They are very cheap — I got one for £18.69 including tax & delivery.
Edit: I had to close the comments on this post, as it is a magnet for scummy spammers posting “oh that’s great” with a link back to their own site selling these toys. Sorry about that — some people spoil it for everyone.