probably a billiard game 
+1...since omgpop I know no where to P2P people via Bitcoin in pool.
I'd play.
I'm sure there's websites out there, just not well-known.
I also enjoyed OMGPop and I personally can't find any sites that allow you to P2P via sharing a link. It's hard to do private matches with friends or other gamblers by trying to get into the same lobby.