Windows7 beta comes with three internet games that may look like games that are present in Windows XP. Windws7 team completely redesigned the three games and they have improved these games a lot as compare to old version of games. Users can also track their statistics while playing the games.
Internet Backgammon:

Internet Checkers:

Internet Spades:

Windows7 internet games features
- Play online against human opponents (up to 4 players at the same time with Internet Spades).
- Select from 3 skill levels to be matched with similarly skilled players from all around the world.
- If your opponent drops out, a computer opponent takes over to finish the game.
- Choose from cool different backgrounds and piece/card designs.
Source:The Windows Blog