I pre-ordered a Raspberry Pi a few months ago and it arrived last week. It still sits on my desk in it’s box waiting for a use. Basically, it’s a credit card sized, ARM-powered computer that can run Linux and costs about 35 dollars. All you need is an SD card for the OS and a USB power supply that provides the right voltage.
I’m thinking of using this as a video streaming device for my living room, since it has onboard HDMI that can output HD resolution. I would take my Linux video server that is currently connected directly to the TV and make it headless in a closet, then rig up the Pi behind the TV with a USB wifi adapter and a bluetooth adapter so I can connect a mouse and keyboard. It could get wired directly to my router since it has onboard LAN too. Once I get this all up and running I will post my impressions of it, but right now it remains a curiosity in an anti-static bag.