Odroid has released a new set of Ultra compact ARM based boards. Smaller Odroid-U2 is only 48x52mm in size (less than credit card), its big brother being 90x94mm. Both devices have quad core ARM processor (Samsung Enyxos 4412), with 2 gigs of RAM, MALI-400 quad core GPU, 10/100 Mbps LAN, USB 2.0 ports, HDMI port and MicroSD/eMMC sockets.
These computers are able to run Android or Linux based OS (E.g. Ubuntu) and there is already few videos in the Youtube where you can see these tiny computers in action.
See more information from the manufacturer’s site: ODROID – product catalog
And check the great videos from: ODROID videos on Youtube