According to this new story at the BBC, the folks at the Relativistic Heavy Ion Collider are actively trying to make black holes. Sure they're small now, but just like that cute baby pet aligator, they're bound to get larger, and pretty soon, the sewers are swarming with them. Wait, someone already made a move about that. Nevermind.
Still, while making something 10,000 times hotter than the sun was pretty frightening, at least it only hung around for a few femtoseconds. A black hole, if it doesn't immediately burn itself out (by converting its mass into Hawking radiation), its going to start eating everything it can get its hands on, growing bigger and bigger.
Yes, playing with black holes sounds really neat, but the law of unintended consequences seems to be relevant here.