If you thought the user-generated content phenomenon began and ended with video, think again. Since launching last December Microsoft’s user-generated game hub XNA Game Studio has experienced more than 400,000 downloads of its make-your-own video game software by would-be creators. And XNA has just wrapped up its Dream-Build-Play game development launch contest, which encouraged both amateur and pro game developers to design innovative video games for Windows or Xbox 360 platforms using the free software.

Tied for first place are Canadian David Flook’s action-robotic sports game Blazing Birds and New Yorker James Silva’s The Dishwasher: Dead Samurai, a highly stylized fighting game. The winners have been offered publishing contracts with Xbox Live Arcade worth US$10,000 each.

A total of 20 entries were tapped as finalists from the more than 4,500 submissions received by Microsoft.

Moving forward, XNA Game Studio will continue operating under its subscriber-based model that empowers users to download game assets and then post their own versions to the hub, where other participants can evaluate and play them.