I just bought one of these little beauties, the
StickDuino
, and its tiny size is awesome. There are no tricks of perspective here, it is almost exactly the same size as my old work-horse SanDisk USB Stick, although a tiny bit wider. Aside from the sub-$20USD price-tag, the best bit is the integrated USB chip + connector, something that made the "package-arrived" to "blinking-LED (hello-world) program running" process about 3 minutes (the time it takes to install the drivers and un-rar the IDE).
My intention is to have this attached to the back of my Robosapien V1, with an IR LED for control, or to the CMUCam for a little cat-tracking robot!