A colleague in the office has been into this for ages. He's got several radio-controlled helicopters, these things are massive and you don't want to be anywhere near 'em, the blades could chop your head off. Anyway, he was telling me he was flying one of these (which apparently are very tricky to fly), he lost control and it actually flew into an open window in an HDB block. Needless to say he didn't try to retrieve it.
This guy is quite a nutter, he's also got a motorised skate-board, he was out on this going downhill when he remebered there were no brakes so he threw himself off and was pretty badly bruised. I tried to interest him in motorcycling but he thought that'd be too dangerous!