The Raspberry Pi is a $35 single board computer with an incredible following. Add on hardware ranges from motion sensors and GPS receivers to phone line boards.
The main board is powered by an ARM1176JZF-S 700 MHz processor and has HDMI, EThernet, USB2,Analog video and Analog audio interfaces. It is powered by a single 5V mini-usb connector and has pins that connect to both voltage and GPIO lines. There is 512M of on board RAM and an SD connector for the host OS. I configured my board with a 16G SDFlash module which leaves plenty of room for additions and media.
The OS can be a custom version of debian Linux called Raspian, Android or the XBMC media server. Immages are avaible on line for all of the OS’s and software is available to make programming the SDFlash easy on both Mac and Windows platforms. The on board H264 decoder has no problem keeping up with an HD1080P video feed making the Pi and ideal media controller. XBMC provides on screen controls so you can select media using an IR-Remote or remote control software on your IOS or Android device.
There are a number of cases available for the pi that range in price from a few dollars to more than the price of the pi itself. I personally have a difficult time paying more for the case than the computer but the thing about the pi is that every user gets to make their own choices.