Sapiens is a shareware application launcher that tries to mix mouse gestures (a circular motion with the pointer invokes it, even when dragging a file) and radial menus (filled according to your previous choices and some context):

It may be appealing to people requiring Accessibility enhancements, but in terms of speed and efficiency, it still has a way to go before being as quick and intuitive as Quicksilver (which can support mouse gestures and radial menus through plugins).