The T-Qualiser is a shirt with embedded graphic equalizer:
Simply wear it while the music is playing and watch the panel come to life as it flashes to the rhythm of the music. Yep - it really does have a graphic equaliser on it.
http://www.t-qualiser.com/ [Flash] - Thanks Hanah!
It uses four tripple A batteries that you put in a plastic case which can be placed in a fabric pocket inside the bottom of the shirt. On the plastic case there is an input gadge that can be adjusted how sensitively the shirt reacts.
A spectrum display, maybe, but an EQ, no... unless all the knobs are on the inside and the shirt comes with gigantic noise-canceling-type headphones that cover the entire room so the shirt can boost some frequencies while suppressing others.
Neat, though. Sadly, around here you'd probably get arrested on some BS "glowsticks = teh drugs" anti-rave law if you wore it in public.