Raspberry Pi Computer Board
Tiny, low-cost Linux computer
I bought one of these a few weeks ago for use in home automation projects, the first of which is an RFID – controlled door lock to my shop. It is easy to use for anyone even sightly familiar with Linux, and is quite inexpensive ($29 for the Model B). Networking is plug-and-play, and there is massive support from its user community.
It is about the size of a credit card and is powered by a USB charger (not supplied). Many accessories are available from multiple suppliers.
This is an excellent learning tool for people who want to know more about computers than how to run common apps like Microsoft Office. It is cheap, small, and very well supported for users of all skill levels.04/6/15
(I have a Raspberry Pi. The first thing I did was install Raspbian, a version of Linux, on it. Then I installed a Minecraft Server on it. I bought a $10 USB WiFi stick and a cheap SD memory card to make it more useful. It also has an HDMI port so you can use it like a regular computer. It's pretty amazing how much you can do with one of these. - Mark Frauenfelder — editors)