ATs, all-in or fold?

[AKA Squared]

The situation is a bar tournement; no buy-in, although buying things from the house (e.g., drinks) gets you extra chips. First and second place get money, third gets a gift certificate. The nine people at the final table get points toward other prizes (the largest of which is a buy-in to a WSOP satellite).

Hero is at the final table. Ninth place is gone. His stack is smaller than the big blind, so his only options are all-in or fold. In middle position, with several callers, he gets ATs.

Hero's move?