-Synesthesia: A neurologically-based condition in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway.
-Grapheme-color synesthesia: Letters or numbers are perceived as inherently colored.
-Ordinal-linguistic personification: numbers, days of the week and months of the year evoke personalities.
-Number-form synesthesia: Numbers, months of the year, and/or days of the week elicit precise locations in space.
-Sound-color synesthesia: voice, music, and assorted environmental sounds such as clattering dishes or dog barks trigger color and simple shapes that arise, move around, and then fade when the sound stimulus ends.
-Lexical-gustatory synesthesia: spoken or written words evoke vivid sensations of taste, sometimes including temperature and texture.
http://en.wikipedia.org/wiki/Synesthesia#Sound_.E2.86.92_color_synesthesia
