Rainmeter is a fantastic desktop customization tool available for Windows. Unfortunately Rainmeter is not available for Mac. For Mac users Übersicht is a desktop customization tool and alternative to GeekTool. Using Übersicht you can build custom widgets anywhere on your Mac OS X desktop.
Must read: GeekTool is a Rainmeter alternative to Mac
Übersicht lets you run system commands and display their output on your desktop in little containers, called widgets. Widgets are written using HTML5.