Like so many others I grew up programming the ZX Spectrum and in latter years have taken to php/mysql programming and have dabbled a bit with PIC programming. Was very excited to hear of raspberry pi. I'm listing here my intentions in case others are interested in collaboration...
1) Greenhouse control system - monitoring temp/humidity etc and controlling watering and ventilation systems etc
2) Automated chicken house - when I get a chance I will try to get my chicken house automation web pages back online
3) Model rocketry - altitude/GPS
With each of these I'm interested in wireless telemetry system to receive data remotely as the projects won't be within wifi range of my main PC and there is no option for an ethernet cable. So some sort of radio comms will be necessary.