The Wii Remote is fun to use especially in a party setting, but some people have complained that it isn't as sensitive as they would like it to be. After all, where you place the sensor bar is extremely important, as direct sunlight pouring into your room and directed straight at the sensor bar is a big no no. With the Wii MotionPlus peripheral, this add-on accessory hopes to make your 3D gaming experience all the more accurate and lifelike. It is connected to the end of the Wii Remote and "allows for more comprehensive tracking of a player's arm position and orientation, providing players with an unmatched level of precision and immersion. Every slight movement players make with their wrist or arm is rendered identically in real time on the screen, providing a true 1:1 response in their game play." There is no word on pricing or availability though.
Source: Uncrate