Basically: @tmm1 has found an initial way to add custom Siri commands, starting with integration with @github's hubot.
Hubot is a library and an executable that wraps up all the logic of connecting to chat servers. Right now there are adapters for Campfire and IRC. Hubot simply idles and waits for specific chat strings. Once it receives those strings it will perform an assigned action.
Tmm1 has posted the following screenshot showing the accomplishment.
Read More [via Alton]