"Rock Band is a series of music video games developed by Harmonix Music Systems and MTV Games, and distributed by Electronic Arts for the Nintendo DS, iPhone, PlayStation 2, PlayStation 3, PSP, Wii, and Xbox 360 game systems. The series, inspired by Harmonix's previous efforts on the Guitar Hero series, allows up to four players to simulate the performance of popular rock music songs by playing with controllers modeled after musical instruments. Players can play the lead guitar, bass guitar, and drums parts to songs, as well as sing through a USB microphone. Players are scored on their ability to match scrolling musical "notes" while playing instruments, or by their ability to match the singer's pitch on vocals.
The first game in the series, Rock Band, was released in 2007 shortly after Harmonix was acquired by MTV Games, and its sequel Rock Band 2 was released in 2008. Harmonix has also regularly provided downloadable content, in the form of additional downloadable songs on a weekly basis through the game consoles' network services. To date, over 1000 songs are available between those on the game discs and through downloadable content. Harmonix has also created standalone Track Packs that either contain a selection of downloadable content, or a selection of band-specific songs. The company has also designed the Rock Band Network to allow bands and labels to publish their songs as Rock Band tracks that can be purchased by players. To date, over 13 million copies of Rock Band titles have been sold netting more than $1 billion in total sales. Over 1,000 songs are available in the franchise library, and over 60 million downloadable song purchases have been made"
Source: Wikipedia, "Rock_Band", available under the CC-BY-SA License.