PocketMod

I found this nice little diary/organiser a while back while browsing lifehacker and figured I'd share it here.
It's basically a diary made from a folded up piece of paper. It benefits over a normal diary or PDA by being very small, it will easily fit into a back pocket or wallet. You don't need to worry about damaging it and it's completely recyclable.

All you need to do to get one is visit the link at the bottom of this post, click "Create PocketMod" and you're on your way to a stylish pocket diary.
You will be presented with a simple little interface that allows you to drag and drop different page layouts on to any of the eight available pages. The list options it gives you is surprisingly large, it will allow to have anything from simple a week or day per page diary to a randomly generated sudoku puzzle.

PocketMod.

Here's video of folding instructions.