Wii MotionPlus /// $20

The Promise: When it hit stores in 2006, the Nintendo Wii's motion-sensing capabilities were revolutionary. But they really aren't that sophisticated or precise—most in-game actions involve broad swipes, with little room for the nuance necessary for actions such as sword (or lightsaber) fighting.The Wii MotionPlus attachment clips to the bottom of the Wii controller and, when paired with compatible games, boosts its motion-sensing capability and precision (Nintendo claims it offers true one-to-one sensing).

In Practice: The peripheral just came out; there are only a few games that support the MotionPlus right now. We tested it with Wii Sports Resort—the bigger, better sequel to the Wii-bundled Wii Sports. It was clear that with the MotionPlus, the Wii-mote's motion-sensing capability is vastly improved. The original Wii Sports Tennis game was certainly fun, but playing it involved little more than wildly swinging our arms at the right time. Wii Sports Resort's updated Table Tennis game uses MotionPlus to allow for all sorts of moves: backhanded swings, backspins, power slams. And then there's Resort's sword-fighting mini game. Ever since the Wii was first announced, gamers have been dreaming of realistically recreating sword fights—something that has quite simply not been possible with the technology (at least in any fun way) up to now. For the first time, we actually felt like we were in control of our character's sword, parrying and striking our opponent.

Bottom Line: MotionPlus adds a much-needed extra dimension to Wii game play. Up until now, much of the system's motion-capturing functionality has felt clumsy, unnecessary and gimmicky. This makes it realistic. But like any gaming peripheral, its success is contingent on there being a decent number of games that support it. If developers latch on, it could be enough to add a few years to the Wii's shelf life. And they'll need it, considering the looming spector of Microsoft's own attempt at motion-capture: the much-hyped Project Natal. —Seth Porges