Image via WikipediaMass DDR at the Videogame Expo. They had 32 people all dancing at the same time on wireless metal dance pads. The screen at the front showed a bubble for each player to let them know beat by beat how they're doing. The top 10 scores (and dancer numbers) were shown oat the bottom of the screen. And people were having a great time. It wasn't just kids or girls - everybody was dancing together. The man running the show played songs at different difficulty levels so everybody could have a good time.
(ps - this was my first attempt at using the FlipVideo I borrowed from school - the quality is pretty awesom considering I was in a darkened room, on the floor, holding the camera propped on my knee)
Here's the video