Sonic Riders series

The Sonic Riders series is a collection of racing games, in which Team Sonic part take in Extreme Gear racing against their rivals the Babylon Rogues in various racing competitions such as the EX World Grand Prix.

The Sonic Riders series introduce the sport Extreme Gear Racing as well as Babylon lore to the Sonic the Hedgehog series.

Games
So far, three games have been released:
 * Sonic Riders for the Nintendo GameCube, Xbox, PS2 & PC.
 * Sonic Riders: Zero Gravity for the Wii & PlayStation 2.
 * Sonic Free Riders for the Xbox 360. (Kinect required.)

Trivia

 * Such futuristic locations as Future City and Monopole have been established in the series.
 * Everyone wears sporty attire as racers, such as new shoes, gloves or eye-protection. Amy Rose and Dr. Eggman who appear in usual clothes in cutscenes also switch to sporty attire when riding Extreme Gear.
 * Superstars can also be unlocked and playable in these games along with Sega themed courses.
 * NiGHTS, Ulala and AiAi are unlockable in Sonic Riders as well as courses Sega Carnival and Sega Illusion. Opa Opa is also one of the available Extreme Gears to purchase in the game for 2,500 Rings.
 * Amigo, NiGHTS and Billy Hatcher are unlockable in Sonic Riders: Zero Gravity as well as the Sega themed courses '80s Boulevard and '90s Boulevard.
 * Sonic Free Riders is the only Sonic Riders game without additional Sega characters or courses.