I take a break from my IPP posts to become a bit of a puzzle pusher. Phil Tomlinson has a few "Don't Shout" and "Always Empty" boxes up on ebay now. I think these are fantastic puzzle boxs. I played with them over at Allard's and loved them! In fact, He did too. Read his blog post about them, then go take a look at the auctions and place a bid!
(Photos stolen from Allard and Phil.)