To gamble.

To play card games, board games, or video games.

To exploit loopholes in a system or bureaucracy in a way which defeats or nullifies the spirit of the rules in effect, usually to obtain a result which otherwise would be unobtainable.

“We'll bury them in paperwork, and game the system.”

The playing of a game or games, including but not limited to video games and games of chance.

Careful, strategic use of rules to achieve one's purposes, as one would use the rules of a game.