If you are feeling ambitious this real time eye tracking system it completely open source. Download the code and start hacking.

“openEyes is an open-source open-hardware toolkit for low-cost real-time eye tracking. The purpose of openEyes is to provide a hardware design and a set of software tools useful for the analysis of eye movement data. The development of openEyes stems from the recognition in the eye tracking and human computer interaction communities that while the cost of hardware for eye tracking has precipitously dropped in the recent past that the there is lack of freely available software to implement even long-established eye-tracking methods. The tools available for this platform include algorithms to measure eye movements from digital videos, techniques to calibrate the eye tracking system, and example software to facilitate real-time eye-tracking application development. ”

Via: Make