"PaRappa the Rapper is regarded as the first "modern" popular rhythm game. It was followed by a spin-off titled UmJammer Lammy, which was released on March 18, 1999 in Japan. The game featured a new cast of characters, multiplayer modes and focused on guitar play, but very similar game play. A bonus mode was included in which the entire game could be replayed with Parappa as the protagonist, complete with his own versions of the game's stages. An arcade version of the game produced by Namco was also released.
A direct sequel, PaRappa the Rapper 2, was released on August 30, 2001 for the PlayStation 2. The franchise has spawned a large range of merchandising and a children's anime TV series, PaRappa Rappa, which began airing in April 2001 on Fuji TV in Japan.
In 2007, it was rumored that work had begun on a PlayStation 3 sequel entitled PaRappa the Rapper 3"
Source: Wikipedia, "PaRappa_the_Rapper", available under the CC-BY-SA License.