I thought this would be an interesting experiment to evaluate the effectiveness of binaural beat meditation. By using EEG (neurofeedback) signals we could, theoretically, observe the brain waves pulsing at the frequency of the binaural beats.
The chair above features two frequency dials (one for each ear), an envelope adjustment (to smooth the sound), a hacked EEG (which I already have - http://frontiernerds.com/brain-hack), headphones, an arduino, and a CPU. The acousic software could be created quite easily using OpenFrameworks or Processing.
While this experiment likely will not generate any scientifically useful data, it may present an interesting interaction experience for the user - one who is interested in either EEG or meditation.