Many users with "older" video cards don't get the benefit of the cool ripple effect when adding a widget from the widget bar. Clicking a widget simply causes it to appear on the screen.
This morning, I discovered by accident that you can actually drag an item from the widget bar to the screen, and it will "morph" from the widget icon to the final widget shape. Pretty cool! You can even slow-mo it by holding down the Shift key prior to dragging.
[robg adds: I wasn't aware this was possible, and (to me) there's a better benefit than the cool morph: this trick let's you exactly position a widget on opening, which has been one of my Dashboard complaints. By dragging, you control exactly where the widget will be displayed. Note that the morph animation will reverse, too, if you change your mind and drag the not-yet-dropped widget back to the widget bar.]

