For those of you who are interested in different Open Source and *nix-y operating systems, Sun would like you to take a look at OpenSolaris. For those folks who are too lazy to download the ISO of the disk image, Sun will even ship you a copy of the CD to your home or workplace. That's not such a bad deal, and makes such a better drink coaster than the AOL CD-ROMs. Seriously, it might be worth a look if you like messing with different BSD and Linux distributions.
Update 6/27/08 - I came home yesterday to a sparkling new CD from Sun. That is a FAST turnaround. Less than 36 hours!