Automate call forwarding with Bluetooth Proximity Detection

Nerd Vittles has a quite detailed how-to series on setting up a
"Bluetooth Proximity Detection System"
that detects when you're home or not by sensing your Bluetooth device, and routes your incoming calls accordingly. The system is based on the free Asterisk@Home
Linux server, and can also connect with a home automation system to turn on the lights and get that electric blanket of yours all warmed up. They did it all for $50, and that includes purchasing a Bluetooth adapter for the compy and a headset to activate the system in case you don't have a Bluetooth phone (tsk, tsk). A warning though, for the Linux averse: you're going to have to get down with your command line bad self for this one; though they do tell you just what you'll be typing into that terminal of terror.