This work describes how two MIT graduates created a video-game phenomenon "The Beatles: Rock Band." The title, available for the Microsoft Xbox 360, Sony PlayStation 3, and Nintendo Wii, allows gamers to perform along with the Fab Four by singing and playing instruments that work as video-game controllers. The goal is to stay in sync with the music. As a song plays, color-coded dots, representing the musical notes, cascade down the TV screen. The guitarist and bassist must press the corresponding colored buttons on their instruments, and the drummer has to hit the right drum pads. Vocalists must sing on pitch as the lyrics scroll across the top of the screen. The game, created by Harmonix and published by MTV Games, features 45 career-spanning songs and pixelated Beatles characters performing at locations like the Cavern Club in Liverpool and Shea Stadium in New York City. Paul McCartney and Ringo Starr, as well as Yoko Ono and Olivia Harrison, the widows of John Lennon and George Harrison, helped Harmonix pick the songs and tweak the graphics. But the game also stands out for all the music technology behind it. To create the separate instrument and vocal tracks the game needs, Harmonix engineers had to use special audio filters to extract every note from the master tapes. They also developed a pitch-evaluating system that can monitor three players singing harmonies - a key part of the BeatlesÂ¿ music.