From Microsoft:

Over the weekend we pushed out a Zune HD firmware update, version 4.3, which enabled 3-D gaming on Zune HD. Today six new games are available in the Zune Marketplace. The new games take advantage of Zune HD’s beautiful multi-touch OLED screen and accelerometer and some (Project Gotham Racing: Ferrari Edition, Audiosurf Tilt and Vans Sk8: Pool Service) utilize the powerful NVIDIA Tegra processor to deliver immersive, 3D gaming to Zune HD. As with the other games offered for Zune, these games are available for free to Zune HD users and feature a short ad at start-up.

In addition to existing games on Zune HD the new games include:

Audiosurf Tilt: Audiosurf creates a rollercoaster ride from any song. Choose any song from your music collection and watch Audiosurf turn it into a unique roller coaster track for you to ride. The song you choose determines the shape, the speed, and the mood of each track. Tilt your Zune like a steering wheel to collect colored blocks and avoid speedbumps. Unlock more than 30 designs, each with its own special theme and color palette.

Checkers: Enjoy the classic game of Checkers in a beautiful outdoor park setting.  Play against the computer or against a friend.

Lucky Lanes Bowling: Bowl in different game modes: exhibition, blackjack, golf. Play in five different bowling alleys with unique themes, all with the swipe of a finger. Choose from twenty different bowlers and twenty two different ball styles. You can play against the computer or play with up to four friends.

Piano: Play your own tune, or play along with your favorite music on this electronic piano.

Project Gotham Racing: Ferrari Edition: Tear through the streets of London, Tokyo, and New York in the Ferrari of your choice using multi touch controls and the built in accelerometer.

Vans Sk8: Pool Service: From the Admiral to the old abandoned rec center pool, Bucky Lasek and Omar Hassan know a good bowl to skate.  Hit the pools and put these Vans skaters to the test with all the tricks in their bag and achieve hero status once you unlock their pro model skateboards.

We're excited to be bringing these games to Zune users today. And, as we’ve said in the past, we will be delivering additional applications for Zune HD including Facebook and Twitter in the future.