Judging by the response to news that Valve was readying an official Weighted Companion Cube plush, demand for such a tchotchke is sky high. The good word from the boys and girls at Valve is that the silent star of Portal is now available in huggable polyester fibre, measuring 6" by 6" by 6" (about 15 centimeters cubed for our metric friends) and can be yours for only $US 29.99.
The product frenzy doesn't stop there, though, as Companion Cube fuzzy hanging-dice, Aperture Science mugs and Cake posters are all available in the store. Don't forget, though, that a life-sized Weighted Companion Cube is being auctioned off on eBay, with proceeds going to Child's Play.
Weighted Companion Cube [Valve Store - thanks, Peter!]