Yesterday, we reported that one of the newer faces at Valve was now working on next-generation gaming hardware.
If that wasn't enough fuel for the fire then check out one of the latest vacancies at Valve for an Electrical Engineer.
In the job posting they clearly state they are "developing hardware" and not just "me-too mice and gamepads" but "whole new gaming experiences".
This could be the next big thing for Valve, or it could just be an extremely experimental project. Either way, we'll keep digging for more information.