A notepad and pen that are so small they fit in the credit-card slot in your wallet:
The size of a credit card, its slim cover contains a pad of 15 self-stick notes and a tiny pen with Flexigrip "wings" for a stable grip. It fits easily in your wallet for instant access anywhere, and pop-up tabs on the top and sides make it easy to retrieve. (3 x 2"; 1 oz)Link (via Popgadget)
Update: AJ sez, "The company which makes that wallet notepad is called Picopad. They have a web site and a WMV [ed - ick] video clip which gives a good idea of its size and usability."