Amen to theat. Antichamber has given me more hours of entertainment than I could ever expect. As one reviewer put it, "The biggest challenge is yourself."
As long as you don't look up solutions, Antichamber is of the best games I've ever played. The solutions are truly your own. The game lets you solve it in your own way. I can't really tell you much about it without spoiling it.
The only thing I can say about it is: Antichamber is best experienced by yourself. Solve it by yourself or you will be cheating yourself of one of the best games you'll ever play.