Recently I found an interesting testnet transaction: 952656e19ce57698880ad6ada935f29ee2cae82c4e7486516908b630671dd84b. It seems to be some kind of puzzle, but probably even the author cannot just move the coins without actually solving it (which is not the case in well-known mainnet transaction 08389f34c98c606322740c0be6a7125d9860bb8d5cb182c02f98461e5fa6cd15). So, if I understand it correctly, the goal is to create any address with as low 160-bit hash as possible and then take these coins. I guess it is on testnet, because of the standardness limits on mainnet. The whole change seems to be quite simple, instead of "OP_EQUALVERIFY" there is "OP_LESSTHAN OP_VERIFY".