If you are looking for a cool Sci-Fi theme, grab this new Windows 7 theme with Hard Reset wallpapers.
Hard Reset is somewhat similar to Serious Sam but also has a pretty cool Sci-Fi settings. The game will be released in less than a week on Steam
Hard Reset Wallpapers
Grab the Windows 7 theme here if you dont want to download the wallpapers one by one:
More gaming themes will be up shortly, stay tuned for more!