Valve has already put Unreal Tournament III on sale until March 15 and let folks play the full game for free this weekend. However their regular Steam weekend update is still in play and today they have put 2D Boy's terrific puzzle title World of Goo on sale for just $4.99. That's 66 percent off its normal price of $14.99 on Steam.

That's not all the Steam news today. The official Criterion Games web site has posted up word that their racing game Burnout Paradise: The Ultimate Box will soon appear on Steam. The racing game was released in full by publisher EA last month in a trial version. You can download the full trial game right here at Big Download.