If you have some coding skills (C# or Visual Basic.NET for example), Google has released the Google Deskbar API.
Google Blogoscope mentions a few of the things could do with it:
+ Locate and play a music play list on your hard drive.
+ Solve algebraic equations.
+ Send instant messages.
We blogged an item about three weeks ago about the Deskbar "graduating" for Google Labs.
Meet Your Favorite Search Engine Watch Contributors
Many of SEW's leading expert contributors will be at ClickZ Live, the new online and digital marketing event kicking off in New York (March 31-April 3). Hear from the likes of: Thom Craver, Josh Braaten, Lisa Barone, Simon Heseltine, Josh McCoy, Lisa Raehsler, Greg Jarboe, Dan Cristo, Joseph Kerschbaum, John Gagnon, Eric Enge and more!