The SIP "redphones" is an idea I really like. My wife managed to get a SIP IP phone from one of her buy-nothing groups that I've been meaning to setup an Asterisk server for just to mess with. Maybe stick it upstairs where my kid likes to play & let him get the experience of using a "real" phone.

It is pretty funny to be able to dial an extension from your desk phone to get the IVR of paultag's Christmas tree, but man does managing asterisk suck.