How do you prevent this: somebody creates machines, then immediately starts launching malicious attacks on other machines?
I run a similar service, and I'm starting to hit this problem. Whoever your network provider is, they might eventually get annoyed when you're hosting attacks that other people complain about...
This is very cool. I wish the terms were a little different though. Eg maybe you get 3 hours but you can only make as new sever once a week. I can't think of what I would do in 40 minutes. But with a bit more time I could see this being very useful for testing various things.
By following this link you will get free Ubuntu 14.04 64bit 512MB ram 20GB space server for 40 minutes.