I find myself playing meta-games a lot. That is, I find a game I like, then find games within the games when I'm bored of the usual means of playing it. For example, back when I played Age of Empires II, I would see how many troops I could get. In the usual game, you were limited to how many troops you could have by a set limit at the beginning. However, with a monk you could convert others' troops past that limit. So what I would do is try to get the computer to keep sending troops and such ad infinitum into the waiting arms of a huge army of monks. The hardest part was to keep the computer from giving up.

In Team Fortress 2, I often find myself more worried about trying to keep as good a ratio of kills-to-deaths as possible.

In chess, I find myself trying two meta games. The first is to not just win, but to win without losing any pawns and converting all of my own pawns to queens without causing a stalemate or checkmate.  The second is to checkmate with as many pieces as possible. In checkmate, the king cannot move out of its current space into any of the adjacent 3-to-8 spaces (3 if in a corner, 4 on an edge, 8 away from the edges). So far I've accomplished the first meta-game (several times), but have never managed to get the theoretical maximum of 9 pieces causing checkmate. My current best is seven: