Download gOS, the operating system of Wal-Mart's $199 PC
And you don't need to buy a $199 PC to load it. You can download gOS right now. Unfortunately, the developer's site seems to be down at the moment, but you can find gOS on several Torrent trackers.
The ISO weighs in at 728 MB, making it a tight fit for a CD-R, but leaving plenty of room on a DVD-R. And like almost all Ubuntu-based operating systems, gOS comes as a LiveCD, meaning you can take it for a test drive without installing anything. Just boot your PC from the DVD. When you're done, shut down, pop the DVD out and reboot into Windows, Linux, or whatever you've been using up until now.