Gate

How the gate is opened

Grabbing the index.php webpage ( in http://pony.noisebridge.net/gate/ or http://pony.noise/gate/ )
calls the shell script gate-www
which will ssh into 172.30.0.31 (the laptop closest to the door)
and run the open-door binary which actually opens the gate

Mercurial Repo

The files for the gate are in a Mercurial repository on pony in /var/hg/gate/