Mozilla have just announced the launch of the Things Gateway. Aimed at providing a common interface for various non-web-enabled wireless devices to get them onto the internet, the Things Gateway is fully open-source and is an implementation of a “Web of Things” gateway.
Currently, the gateway supports Zigbee and Z-Wave smart plugs, but other devices should be supported soon. You will need a Digi XStick (ZB mesh version) for ZigBee support, and the Aeotec Z-Stick (Gen5) for Z-Wave—although other OpenZWave compatible dongles may also work.
The API documentation is available here, Mozilla’s official announcement is here and you can download a pre-configured OS image here.