I've just discovered and received today an amazing piece of hardware that a lot of you might find useful. It's called the Tobii Eye Tracker 4C https://tobiigaming.com/product/tobii-eye-tracker-4c/, which can be used with the Tobii Pro Sprint https://www.tobiipro.com/sprint/ hosted service.
I've recorded a video demo of it here: https://www.mediawiki.org/wiki/File:Tobii_Eye_Tracker_4C_demo.webm
This could allow us to do lab user testing where we record gaze cheaply and very easily.