The series Pac-Man World (パックマンワールド Pakkuman Wārudo) was first released in 1999 on the 20th anniversary of the creation of Pac-Man by PlayStation and Game Boy Advance.
The story line begins when Pac-Man arrives home on his 20th birthday (the game was released to coincide with the 20th anniversary of the original Pac-Man in arcades) only to discover that his friends and family—Ms. Pac-Man, Baby Pac, Pac Jr., Professor Pac, Chomp Chomp the dog, and Pooka have been kidnapped by the evil Toc-Man, who is a giant robot Pac-Man impersonator that was created by Orson, who is bent on stealing Pac-Man's identity. Pac-Man sets off to the Ghost Realm and works to free them, each of whom is held captive in one of the different worlds. (Pirate world, Ruins world, Space World, Circus world, Factory world and Toc-Man's Mansion).
The gameplay generally was that of a standard 3D platformer that played heavily into the history of the character.
There was a Game Boy Advance version in 2004. Due to hardware limitations, many features were left out of the game, such as Maze Mode, the original Pac-Man and many levels cut out. There was a sequel, Pac-Man World 2, on February 24, 2002. It is available on the PC, PlayStation 2, Nintendo GameCube, Xbox and Game Boy Advance.
Pac-Man World 3 was released in 2005. This game introduced new moves and powers to Pac-Man and gave him a full voice.
The latest game in the series is the spin-off Pac-Man Party.
Source: Wikipedia, "Pac-Man World", available under the CC-BY-SA License.