The setup of the game sounds a lot like the scrapped 1 vs. 100, which ran on Microsoft's Xbox Live Primetime platform allowing players to compete with other users during live, hosted shows for prizes.
The email teases that players will "compete against your friends and thousands of other players around the world live in Texas Heat poker game shows. What is Texas Heat?
Texas Heat is an exciting and fun new way to play with lots of surprises and more ways to win! With every regularly scheduled episode, you'll be able to bet, raise, and bluff your way to the top table. Be bold and earn big rewards like massive XP and chips for your bankroll. Every show is a new chance to play, win, and compete against thousands of players around the world.
The game also promises "unique tells and avatar accessories." It is unclear if players will be earning real world rewards like Microsoft Points or other goodies. The beta of 1 vs. 100 did not give out real rewards, while the real game did.
1 vs. 100 was a great, social game for the Xbox 360, but it was canceled. It is easy to speculate that the cost of the license to a television game show hurt the project for being cost effective. An original poker show is a great way to solve this problem as Microsoft will own the IP to Texas Heat and I hear poker is still pretty popular.
That is, of course, if this is at all true. Shacknews has contacted Microsoft to determine if this email is legitimate. It certainly sounds like it is, though.