Go Fanboy has confirmed the release of the Green Day Rock Band demo on Xbox LIVE Marketplace exclusively for the Xbox 360. They're reporting the download size of the game as 307mb.

Good news for all you American idiots as Harmonix and MTV Games has released a demo for Green Day: Rock Band exclusively for the Xbox 360. The demo comes in at around 307 MB so you won't have to clear any extra data to enjoy the game. Experience the rise of Green Day from hometown punk heroes to worldwide musical vanguards. All your favorite tracks are here, including songs from Dookie all the way up to 21st Century Breakdown. Relive the famed punk scene of the early '90s and carry the banner of rock music into the 21st century.

AcFreeze via gofanboy.com »