WinDirStat - WinDirStat is a disk usage statistics viewer and cleanup tool, inspired by KDirStat.
Wallpaper Engine - Wallpaper Engine enables you to use live wallpapers on your Windows desktop.
WizTree - WizTree quickly finds the files and folders using the most space on your hard drive. It scans the MFT (Master File Table) instead of crawling the entire disk which makes it very fast.
Lively Wallpaper - What is it? Lively is a Free and Open-Source Software (FOSS) for animated desktop wallpapers.
SpaceSniffer - SpaceSniffer is a freeWare (donations are welcome) and portable tool application that lets you understand how folders and files are structured on your disks.
ScreenPlay - Open-source and cross-platform Wallpaper, Widgets and AppDrawer app.