This is basically a post for *NIX newbies because I'm sure that most of the senior members probably know about this. Basically, what Compaq has done is created dozens of high power machines each running a different OS or on a different platform. If you sign up, you can test and use all of these machines by just telnetting to any machine and logging in.
The OS's include Red Hat Linux 7.1/7.2, Debian/GNU Linux, Slackware Linux as well as Free/Open/Net BSDs. A list of OS's and detailed instructions as well as instructions on how to sign up can be found at:
Hope some of you find this useful,
PS: Please do not try to crack/DOS/bring down these machines because that'll both make you lose your account as well as bring down a valuable community resource if you succeed.