The Reliant ornament lights up when you press a button on the bottom. (Sadly, it does not yell KHAAAAN!.) The "Tribbles" one has a motorized mechanism inside it that cycles the little tribbles around and drops them through the open silo door on the captain's head, as they fell in the original scene. (It also plays a sound clip of McCoy exuberantly telling his discovery of how to stop the tribbles from reproducing. "Now he tells me.")
See, I told you they had a surplus of Awesome.