Another board designed to ease people into using the Pi to control the world around them is Pi-Face Digital.
The credit-card sized board allows users to write programs to control lights and motors, as welll as receiving data from sensors and switches.
Switches, LEDs and relays are already included on the board - so it can be used without soldering - and writing the code to control it is made easier by libraries in C and Python programming languages.
As an example of what the Pi-Face can do check out this video of a robot bird that reads the latest Tweets from a Twitter feed.
One word of warning, at present the board's makers say users need to be familiar with coding if they want to use the board. However they are working on making it easier to control the board using Scratch, the simple drag and drop programming language designed by MIT for kids.