How do I delete games I don't want to play???

I keep getting challenges that put me way over my limit of 15 games. I don't have the time to play them and now they are skulling me even though I have not made a move

In the navigation bar above, click "My Settings" then "My Challenge Settings". Under "Game Limits" enter 0 if you wish to receive no unrequested challenges. There are also controls for limiting ratings and time outs.

Any game you have not moved in can be deleted. Look for the trash can icon in your game list (you may have to scroll to the right) and click it.

I've made a move but my opponent has not moved, and the opponent's time has expired. How do I remove the game from my list?

Follow Monty Moose's advice above. It applies to all games where either player has not made two moves.