Microsoft's new version of Windows, Vista, is still in Beta (testing). You can get a free copy by answering a short quiz on the Vista features. It's a basic quiz. I guessed my way through and got all 8 questions correct.
If you are interested in it and have at least 512 MB of memory to install it, I would encourage you to get a copy.
As one of my Wanaque students once said, "If it's free, it's for me."