The beta release of Ubuntu 10.10, aka "Maverick Meerkat", has been out for a while, and if all goes well the official release will take place on October 10th (10/10/10, whether you follow English or American date notation). It shouldn't be long before the countdown graphic shows up.
For those who don't know, Ubuntu is a distribution of the Linux operating system, based on Debian Linux. If you use Windows and have yet to try Linux, it's easy to do without disturbing your current setup. Live CDs make it trivial, or if you are willing to devote some hard drive space to the purpose, Wubi lets you do so without the delays of retrieving programs from the CD and uncompressing them.