Rainmeter is so super because you can customize it in almost every way imaginable. Everything from the themes and skins of the program to the tray icon can be tweaked.

Features may vary from skin to skin, I came across some skins which include shortcuts to frequently used programs, clocks, calendars, notes, News, Docks, social networking, media player, network information, volume icons and lot more. Each theme can be reconfigured in a wide variety of ways, as each individual module can be dragged and dropped anywhere on the screen.

Also there are thousands of skins available in internet designed by Rainmeter fans. You can found Rainmeter skins in Deviantart and Customize.org .