World Of Goo!

I've gotten a little side-tracked... my girlfriend's son introduced me to "World Of Goo".  I love these types of puzzle games (I reviewed LineRider earlier).  This one is exceptionally well done because of the "Physics Engine" and Artwork.  Basically you build structures out of "Goo" and try to reach a goal.  I'm supposed to be learning Ruby/Rails this week... this derailed me for about a day... oops!