How about arcade machines that take credit cards, and allow 2 or more players to compete for a wager in gambling legal areas? The machine could take a % or fixed fee, and bets on game outcome could be arcade in length and of arbitrary or fixed amounts. This might also be a neat way to do arcades. Another option might be a prize dispensing computer in an arcade shaped cabinet with some usb motors so when the player wins a good score they get a prize, maybe a small prize for an ok score, also probably a good idea for these to take credit cards or paper and coins. Note that if you link your arcade cabinet to the internet via 3g or whatever, you can update it and add/modify games.