I recently discovered this page which lists all verified contracts on Etherscan. From here you can easily see which Ethereum Games are most active.
http://etherscan.io/contractsVerified?sort=txcount&order=descIf you click on one of the addresses, you will be able to view the source code for that contract.
Just thought I'd point it out in case anyone has not seen it yet. Lots of great code examples if you are trying to learn.