I made the smart contract for https://www.ethbowl.com
where you bet the superbowl winner. Concept is quite simple, after the winner is announced, all the bets are divided to winners proportionally of their bet sizes and winners can withdraw their winnings from the site. Contract owner takes the 2% rake from the loser's pot after payouts for winners have been set.
Verified contract is here: https://etherscan.io/address/0xba1e1663316245463d82bc239a4461ba7befb741#code