Here's a simple little AppleScript I wrote a long time ago and then forgot about completely. So much so that I had to download it from MacScripter because I no longer had a local copy. I updated it and made it a bit more user friendly. All it does is turn dashboard off and on. The original purpose was for Musicians who needed all the horsepower they could get from their computers. Dashboard was a bit of a resource hog, but has been improved greatly and of course computers are much more powerful today then back then.
The purpose today is that it's a great if you simply don't want dashboard running or you want to test a widget preference loading and do not want to log in and out of your computer. This mimics the process.
To use it, just place it somewhere on you computer and click on it. A little dialog box will show up and ask you if you want to turn off or on dashboard.
2012 - 01 - 06 - Update: Stays open until you hit cancel button. Added an icon so it's prettier. :oP