A nice source of gaming rumours on the Internet is the Twitter-user Supererogatory, and through him/her/it comes this tidbit of information - seems like Sony have registered three new domains for themselves. The domains in question are called myeverybodydance.com, mydancegame.com and everybodydancegame.com.
In other words, it looks as if though Sony might be ready to reveal a new dance game, probably during E3, to take on the successful titles on the two major competitor platforms - Just Dance on Wii and Dance Central for Xbox 360 Kinect.