Well, I've looked into safe levels, undef, and why's sandbox, but none of them fit my situation very well. Safe levels won't allow players to use game libraries, and I can't find a way to use them in why's sandbox, and undef would be unreasonable. I would have to undef every standard library function. Looks like these are my only choices though, so does anyone have an idea of how to let them use my libraries? Oh, and Rick I looked at Core Wars, and Darwin, and that gave me some inspiration. I don't want my game to end up like Darwin, which will be hard to accomplish (for instance, someone could make an impenatrable Firewall very easily, just by saying Packet.block or something). I also need a real objective to give my players, but I don't want it to be levels or a definitive score. But that is a problem for the future, so letting players use my libraries but not stdlib's is the current problem. -- Posted via http://www.ruby-forum.com/.