I'm going to have to ask, why not replace the outlet with a grounded outlet? Minimal expense, you were at Home Depot already, and you could probably do it yourself. Other than that, pull the grounding pin as Albertporter suggested. If you have a friend in the U.S., contact him, I know there are plenty of the cheater plugs in hardware stores, it could be mailed to you. These are all $1 solutions to the same problem.