BulletAsylum by UberGeekGames is a gorgeous game for Windows Phone 7 that’s part Missile Command, part Geometry Wars and all awesome. It’s written using XNA and coming soon to both WP7 and Xbox live and coming out later this year.
Here’s their blurb:
BulletAsylum is a new spin on the classic defend-the-city-from-meteors genre. Simply touch the screen on a WP7 device, or push the thumbstick on the Xbox 360 to create a literal fireworks show out of your enemies with an impenetrable wall of firepower. Instantly purchase new towers and cities without breaking up the action. Split your fire in two directions by touching the screen in two places or using the right thumbstick. Unleash the screen-clearing Overdrive when you're in a tight spot.