Here's the link
http://www.wolfire.com/humbleFor my part, I can only say that you should do it, even if it's just for 1 buck. There are some really fun games in there that are definitely worth a look.
-World of Goo is a little gem - I think Satis has played some of it. Very neat.
-Penumbra: Overture is a heartstoppingly good FPS adventure/horror game. Not for the faint of heart, but extremely well done.
-Gish is pretty cool, nice art design, fun to play.
-Haven't played Aquaria but heard it's pretty good
-Never heard of Lugaro
In short: must-buy if you don't own any of these games.