Install Mythbuntu 8.10 from Windows with Wubi
Mythbuntu 8.10 incorporates many of the updates that you'll find in a stock version of Ubuntu. It uses the Xfce 4 desktop environment, but if you use your Mythbuntu system primarily as an operating system you'll rarely see the desktop.
One of the coolest features in Mythbuntu 8.10 is support for Wubi. What Wubi does is let you install Mythbuntu (or Ubuntu) from within Windows as if it were just another Windows program. Once installed, you can reboot your system and just select the Mythbuntu option at boot. This makes it easy for anyone who's ever wanted to try Mythbuntu or MythTV to take it for a spin without repartitioning your hard drive. If you don't like it, you can just uninstall Mythbuntu from the Windows add/remove programs utility.