A: Oddly enough, even though most of us can't even imagine what it would be like to taste music or smell the color red, those with synesthesia can and do that every day. Just as the word anesthesia means "no sensation," synesthesia means "joined sensation." For some reason, stimulating one sense will trigger perceptions in another sense.

For example, a bright light might seem loud, the sound of a bagpipe sour, the color after sex a static silver. No one's quite sure of the cause, but there are a few hypotheses. Some experts think that crossed wires in the brain cause the problem (the path to the taste buds gets hooked up to the sense of hearing path, for example), while others believe it's due to a lack of inhibition (when the natural pathways that squelch irrelevant sensory input just aren't working properly). Either way, the phenomenon seems like quite a trip.