Valve's Steam service has announced its regular weekend sales reductions and this week we have a couple of deals to let you know about. The first is for Multiwinia which just had a new demo released. The Introversion Software multiplayer strategy game is now available on Steam permanently for just $9.99. This weekend only, you can also get the first game in the series, Darwinia, for free with any Mutiwinia purchase.

The other weekend sale is for The Ship, the innovative first person action game from developer Outerlight. The game just got a major content update via Steam that adds a new map, new gameplay modes, new player characters and more. For this weekend only you can download and purchase The Ship for just $4.99, a 75 percent savings.

And just as an aside, Steam has added quite a few small and indie based games to their service this week including Spectraball, Galactic Bowling, Space Trader: Merchant Marine and Baseball Mogul 2009.