The Raspberry Pi is a credit-card sized $25-$35 ARM GNU/Linux computer that can be plugged into a TV and a keyboard. Here's a picture of the connectors on the device.
The device is stil under development but here's a rendering fo what it will look like. Should be an interesting alternative to Arduinos but make take a while before it has a good community around it. There's already a lot of interest and activity on the forums. Looking forward to being able to purchase it.