When Microsoft debuted its Zune HD portable media player in September, it also revealed plans to bring 3D games to the device. The company announced a trio of titles that would be available by the end of the year: Project Gotham Racing: Ferrari Edition, Audiosurf Tilt, and Vans Sk8: Pool Service.

　　It's tough to beat free. Microsoft didn't reveal a price for the games at the time because, perhaps, there wasn't one to reveal. Those three games--along with Lucky Lanes Bowling, Piano, and Checkers--have finally arrived on the Zune Marketplace, and all of them are downloadable for free by Zune HD owners.

　　PGR features a dozen different Ferraris and 33 events on London, Tokyo, and New York race courses. Taking advantage of the Zune's wireless capabilities, the game also supports four-player races and time trials against a friend's best run.

　　As the name implies, Audiosurf Tilt lets players control the action by tilting the Zune. The game can make levels out of any song and features more than 30 different themes.

　　Vans Sk8: Pool Service features 10 different events to tear up with Bucky Lasek and Omar Hassan, as well as unlockable board designs. Checkers and Lucky Lane Bowling are self-explanatory, although the latter game also features golf- and blackjack-themed scoring modes. Finally, Piano isn't so much a game as a virtual keyboard with a full 88 keys and a sustain pedal.

　　For more on the latest free offerings, check out Microsoft's official Zune site.