Successfully complete the indicated task in Planet Superstars mode to unlock the corresponding court:

Golden Axe: Successfully complete all Super Monkey Ball missions.
NIGHTS: Successfully complete all Jet Set Radio missions.
Outrun: Successfully complete Exhibition Doubles in the "Outrun" stage.
Puyo Pop: Unknown.
Sonic The Hedgehog: Successfully complete Exhibition Singles in the "Sonic the
Hedgehog" stage.