From Major Nelson's blog!

"This month, Xbox LIVE kicks off the Friendship is Free program. Over the course of this month, multiplayer will be available for all Xbox LIVE members for eight Xbox LIVE Arcade games. The Xbox LIVE Arcade team will open up the multiplayer functionality for A Kingdom for Keflings, Aegis Wing, Bomberman Live, Hardwood Hearts, Hardwood Spades, UNO, Small Arms and Super Street Fighter II Turbo HD Remix.So round up your silver friends and get some free play on."

Come on silvers! join in the fun :p