Ah, there's nothing like the smell of a fresh demo on a Friday morning. Today's Marketplace offering is none other than Sega Superstars Tennis. The demo offers single player and local versus multiplayer. The game brings together plenty of Sega "superstars" (Amigo? A superstar? Really?) for some friendly tennis action and tennis based mini-games. Taking a cue from Nintendo, the game focuses infuses typical tennis mechanics with fantasy court settings and the ability to enter Superstar Mode, which grants special powers to each character. The demo doesn't last very long, but new features are unlocked through successive play-throughs, so give it a shot.