The idea of a reverse Turing Test ("prove to me you are a machine") has been rattling around for a while but AFAIK nobody's really come up with a good one
>>bandra+(OP)
Solve a bunch of math problems really fast? They don't have to be complex, as long as they're completed far quicker than a person typing could manage.
>>bandra+(OP)
Seems fundamentally impossible. From the other end of the connection, a machine acting on its own is indistinguishable from a machine acting on behalf of a person who can take over after it passes the challenge.
>>bandra+(OP)
I'm sure most people are looking for serious takes on this, but here are two SMBC comics on this specific theme ("prove you are a robot"):