http://www.konfabulator.comApple Mac users have enjoyed this product for quite some time. It is now available for Windows users. You can enjoy all the widgets on Windows and create your own cross platform widgets!
The Konfabulator allows you to use Javascript based mini applications that can reside on your desktop. The mini applications are known as widgets and the currently have quite a selection of different ones such as clocks stock quote readers weather, alarm clocks, reminders, etc.
After you install it, you can go back to the site and browse all their other widgets that are available. I love the round clock, weather, calculator, to-do, calendar and one called "paper" that is a translucent notepad (font is a bit small though).
When you find ones you like, just download them and drop them into your My Documents/My Wigets directory and then double click on the file. It will run and be there every time you boot up.
There is also the F8 key that will display them on a plain background and hide them the rest of the time. Handy for those you do not use all the time but like to have handy. You can set this hot key by right clicking on the Konfabulator icon in the system tray (next to the time on your taskbar) and selecting "Preferences".
NOTE: Program only good for 14 days unless purchased (See Kapsules Post on this site in MS Windows recommendations)
Update: July 2005 - Yahoo! purchased Konfabulator and is now making it available for FREE to everyone!!!