If you want to look into Wargames RootHack is a good site.

They host free unix shell accounts on their own network, where you secure your server with your team (6 members) and then try to "disable" the other teams. It's very fun if you know what you're doing (well, for dorks like me anyways). I think we should get an AO team together, it'd own all. ^_^

Anyways, if you're interested here are 2 tutorials on the subject:

The RootHack Survival Guide
MsMittens' Complete Wargames Series Tutorial: PDF


If any AO start a team, keep me updated on it. I'd love to see how that goes.