Dancing is a feature that was added in Patch 126.96.36.199. Dancing is enabled by typing the command "/dance" (or "/tanzen" in the german client, or "/танец" in russian one) while on a planet's surface.
There are 25 different dances, and each hero variant will preform a different one.
On the day the patch was released, a video was released on Darkspore's Youtube channel showing some of the different dances.
Furthermore, a usermade video was made by user "MRgamerus" showing different hero's variants dancing.
Additionally, there is a thread in the Darkspore forums listing all identified dances. All help there will be appreciated! http://forums.darkspore.com/viewtopic.php?f=13&t=6973