a web3 game where you pay 0.02 ETH for a 0.5% chance to win the entire pot, initial money pot starts at 1 ETH and ends when someone gets all the money, literally just gambling, but web3 ;)
Check out pooltogether. Similar approach but the winnings are the yield from the lottery pool and everyone gets their money back :)
As long as gas fees are less than 0.03, the expected value of each bet is positive ๐ค