As a general rule this is how to prevent/beat Realm Down.
Don't create more than 2 games per minute.
Don't create more than 20 games in 1 hour.
If you stick to that you shouldn't ever get realm downed. However; if you are realmed down the only way to get around it is to reset/change your IP address. Resetting your IP will ONLY work if you are on Cable/Dial-Up/DSL and have what is called a dynamic IP address. The easiest way to change it on cable/dsl is to unplug your modem for a few minutes then plug it back in, once it comes back online click Start -> run in the box that appears type CMD or COMMAND depending on your OS, in the dos window that appears type ipconfig -release.
Press enter, then type ipconfig -renew.
You should have a brand new ip address, if you are still realmed down then chances are you have a static IP address and are just screwed for an hour or more. Static IP addresses cannot be changed.
If you happen to be on dial up, just disconnect and redial. Dial-up ip's are always dynamic.