In addition to offering a much simpler Dashboard where your available widgets are presented like apps, Mountain Lion has brought some Launchpad features to your Dashboard.
For example, you can now organise your widgets into folders. This works much like you’d expect. After selecting the ‘+’ sign at the bottom left of the Dashboard interface to access all the installed Dashboard widgets, just drag one widget onto another and a folder will be created :

You can name it whatever you like and start keeping your widgets tidier so it’s simple to find the one that you want:

Also brought across from Launchpad is the search feature so you can now search through your widgets as well. You’ll find a search box up at the top of the screen when adding a new widget:

To access the Dashboard in Mountain Lion: Either select the ‘F4’ key which has the Dashboard ‘speedometer’ icon, or if you have a multi-touch mouse or trackpad you can swipe 4 fingers to the right. (Mission Control also offers your Dashboard at the top left of the Mission Control interface).
This feature has been tested using OS X v10.8.1 which was the latest Mac OS release at the time of writing and also using the latest Internal and external Apple keyboards.