"Lips is a video game for the Xbox 360. Lips was developed by iNiS and published by Microsoft Game Studios. The game features the use of motion sensitive wireless microphones and supports the use of songs already owned through a Zune or iPod...
In addition to supporting single-player, the game allows two players to sing duets or play competitively in various multiplayer modes including "Time Bomb", "Kiss", and "Vocal Fighters". Unlike other music games, except for SingStar, players cannot fail out of a song if they sing badly (or even if they don't sing at all). The game does not have a difficulty setting but rewards players for their singing in six categories including rhythm, pitch, and vibrato....
Lips is bundled with two motion-sensitive wireless microphones (one white, one black). A second player can seamlessly join in the currently playing song by picking up the microphone and shaking it. The microphones can also be used to perform gestures dictated by the game, plus the standard game controllers can also be used to add overlays such as hand-claps and crowd noise.
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Source: Wikipedia, "Lips_(video_game)," available under the CC-BY-SA License.