Use an Ethereum contract and Metamask to put a pool together - like r/millionairmakers except appified. different pools like 100 people put in .1eth and when it hits 100 people in the pool, a random number generator selects a winner who gets 10 eth - low odds of winning but since it's a relatively small group you get to see how stoked the person is who won - or do higher stakes 10 people put in .25eth and the winner gets 2.5 - you get the idea