The Raspberry Pi is a credit-card sized computer board that plugs into a TV and a keyboard. It's a miniature ARM-based PC which can be used for many of the things that a desktop PC does, like spreadsheets, word-processing and games. It also plays High-Definition video.
The Raspberry Pi features 700MHz ARM processor, GPU, 256MB RAM, LAN, USB, SD card socket, RCA video socket, HDMI socket and it only costs £21.60
Read more - http://www.raspberrypi.org/