Raspberry Pi GPIO support
Thanks to apagg there is a Raspberry Pi GPIO device interface available: http://www.agocontrol.com/trac/browser/agocontrol/agocontrol/devices/raspiGPIO/raspiGPIO.py
That makes it very easy and cheap to start with home automation. Just attach relays and binary sensors to the GPIO ports of the Raspberry Pi and configure the corresponding pins to be either an input or output. They will show up as binarysensor and switch devices in ago control.