Transform any computer into a home entertainment system with the HDHomeRun! You can watch, pause, and record Freeview|HD with from any computer on your home network.
With dual tuners you can record one show and watch something else at the same time. Works with Linux, Windows and Mac.
Get started with embedded electronics - it's easy with Arduino, there are loads of tutorials and examples around for this open source platform.
The Freetronics Experimenter's Kit for Arduino is a great introduction, with no soldering required it's suitable for all ages and skill levels.