I'm just laying out the schematic for a GPIO board that includes a 4x20LCD display interface, two mains relays, two opto-isolated mains power sensors, a real time clock chip and interface to some one-wire temp sensors.

The Pi is going to be the master controller for my central heating system. There will be a Web interface and I hope to implement something with a service such as Google Latitude so I can have a 'back from holiday' mode where the system knows when I'm, say, back within 25 miles of the house and fires up the heating and water again.

That's my fun project for when I have some spare time.

Internet Radio Linking Project (IRLP) node. This type of project described here: http://www.raspberrypi.org/phpBB3/viewtopic.php?f=41&t=2... Don't need the portability and I'm cheap and IRLP is proprietary so might go with this instead: http://www.qsl.net/k0kn/cm108_mod.html

Voice controlled smart home - Run siriproxy on it, install lightwave rf lightswitches and sockets, and voice control lights, appliances, XBMC, etc from my phone.

samba & minidlna server

My parents have one sitting in their living room and queue video to it from their iPhone/RAZR from my upnp server and their desktop computer (win7 has a builtin upnp server).