The Raspberry Pi Foundation is like One Laptop Per Child for computer nerds everywhere. No, they're not giving out rugged little laptops to the poorest kids in the world, but they have developed a ridiculously cheap and compact Linux box that even the poorest would-be programmer could afford. The Raspberry Pi measures 3.4 x 2.1 x .67 inches (85.60 x 53.98 x 17 mm) and contains a 700MHz ARM11 processor and Broadcom BCM2835 chipset.
According to the Foundation, that tiny Broadcom chipset is surprisingly capable--they're saying it offers twice the performance of the iPhone 4S GPU and handily beats the now-dated Nvidia Tegra 2 platform. At a targeted price of $35, the Raspberry Pi is a dirt cheap programming box for eager learners. But writing code doesn't make for a very exciting demonstration, so Raspberry Pi got together with XBMC to show the media player streaming 1080p video at a rock-solid framerate.
One of Raspberry Pi's two planned models, the $35 unit, just hit manufacturing and should be available for sale within weeks. The Model B is actually the more expensive Raspberry Pi: it includes an Ethernet port and 256MB of RAM. The even cheaper $25 Model A has half the RAM and no wired Ethernet support. A simple USB wireless stick can get the Raspyberry Pi on Wi-Fi. It'll do AirPlay, too.
The Broadcom chipset can handle 40Mbit/s playback, and there's an SD card port for loading up media. If you don't mind getting your hands dirty, you could build your own media streamer out of a Raspberry Pi for less than $50, and then play around in Debian, Fedora or ArchLinux on the side.