The Z-Nano is the world’s smallest mouse! At a mere 42mm (1.65″) x 21mm (0.83″) x 17.65mm (0.69″), it’s not that much bigger than it’s attached USB cable. The cable even clips into the mouse itself via a powerful magnet for storage. It has a slot that you can slip in your own tiny photo to personalize the mouse. Costs $60 at Flipalbum.