"Actual physical bitcoins" might make a good accompaniment for them, so at the end of the evening whoever won the most could be awarded an actual good-anywhere coin as a trophy. Which they could always bring back next week to give others a chance to win back from them etc.
I agree! It would also be cool to give players at my games the option to purchase some of Mike's physical bitcoins with their winnings. The remainder would go straight to their wallet address.