I agree this is the best so far in terms of ROI likely until someone matches the same fee structure but with more interactive elements like GreedPit or Governmental.
Either that or something which has negative fees by performing a useful function for another group. For example you could provide the bitcoin mixing service for Ethereum while having a game in the contract. When someone who wants to use the game for cleaning ethereum uses a function they would get back 98% instead of %125 ponzi rate but it would be instant. The interaction of the coin mixing could also be used as a seed for random events or bonus within the game. Maybe it's not possible... interesting idea though. (I realize that shapeshifting to Monero is a much better way to do that)