Marvell SheevaPlug

The SheevaPlug looks like a power adapter, but it’s actually a four-inch computer for Linux developers that’s as powerful as some budget desktops but sips a tenth of the power. Developers are using the platform to create a new wave of always-on, Web-connected gadgets, such as the Pogoplug, which gives you access to your external home hard drive from anywhere. Other available SheevaPlug-based devices let you remotely monitor your home energy consumption or watch Web video on an HDTV without having to hook up a full-blown computer. Upcoming plugs will incorporate faster processors, more memory and Wi-Fi to allow more-complicated tasks.
$100; marvell.com