I like a good theme on my Windows desktop and Microsoft have some new ones based around moonlight below.
“Ooh, ooh, ooh, what a little moonlight can do to you! Yes, but how about a LOT of moonlight? This free theme for Windows 7 features brilliant full moons, hazy winter moons, and moons rising dramatically over castles, mountains, cityscapes, and rock formations. Not recommended for werewolves.”
Download from HERE