I have a few suggestions that might help solving the problems. On the player list there are a lot of Brain pawns that haven't played for month.
Delete them from the site.

Something else that might help: close the discussion boards. 90% of the messages doesn't add anything. Brainking is a game site and not a chat room.

Add more member levels all with a limited number of games. For example 150 games for a Brain rook, 250 for a higher level and so on.
Now some Brain rooks play 300 till 500 games at the same time. In my opinion that is not healthy, they need help!