I remember watching a tv program named "Beyond 2000" (obviously, this was last century) which featured upcoming technology. One of these was an ultra-sonic dishwasher. It was supposed to be faster, and use less detergent and water than 'ordinary' dishwashers (though I suppose dishwashing machines in the 1990s probably used a lot more water than they do now). Never heard anything about it again.

(Edit: I mean a full-size dishwasher, not the little devices that are partially immersed in water)