"We Sing is a 2009 music video game for the Wii. Developed by Le Cortex, produced by Wired Productions and published by Nordic Games, it is the first singing game to support 4 players simultaneously each with their own microphone.
We Sing is distributed as a software only version, a two microphone and game bonus pack.
It was revealed in May 2010 that sequel titled We Sing Encore was set for a release in July 2010
The gameplay is similar to the SingStar set of video games. Players are required to sing along with music in order to score points, matching pitch and rhythm. The game has anticheat technology whereby tapping or humming will register on the screen but no points will be awarded.
Multiplayer modes - Group Battle, We Sing, Versus, Pass the Mic, First to 5000. The ability to sing with up to 4 players as a group is a confirmed feature.
Integrates with a USB hub"
Source: Wikipedia, "We Sing," available under the CC-BY-SA License.