Synesthesia

1. Synesthesia:

A condition in which normally separate senses are not separate. Sight may mingle with sound, taste with touch, etc. The senses are cross-wired.

2. Grapheme (color synesthesia):

is a form of synesthesia in which an individual's perception of numbers and letters is associated with the experience of colors. Color synesthesia is one of the most common forms of synesthesia, and because of the extensive knowledge of the visual system, one of the most studied.

3. Ordinal (linguistic personification): 
is a form of synthesia in which numbers, days of the week and months of the year evoke personalities. Personifications tend to co-occur with grapheme-color synesthesia and share many of the characteristics that are definitional of synesthesia, such as being consistent over considerable time intervals and generating concurrents automatically.

   

4. Number (form synesthesia):
is a form of synthesia in which a mental map of numbers, which automatically and involuntarily appears whenever someone who experiences number-forms thinks of numbers.  In particular, it has been suggested that number-forms are a result of "cross-activation" between regions of the parietal lobe that are involved in numerical cognition and spatial cognition.

5. Sound (color synesthesia):

is a form of synthesia which involves hearing sounds in response to visual motion and flicker. Sound-color synesthesia can be further broken down into two categories, “Narrow band”and “Broad band”:

Narrow band AKA music is when music elicit different shades, hues brightness of colors relative to the tones, notes or even instrument played. Broad band synesthesia is when individuals will be able to see colors from hearing sounds of the ordinary (ringing of alarm clocks, people walking, construction, birds flying, besides music.

6. Lexical (gustatory synesthesia):

 is one of the rarer forms of synesthesia, in which spoken or written words evoke vivid sensations of taste, sometimes including temperature and texture. Gustatory synesthesia may be due to increased connectivity between adject regions of the insula in the depths of the lateral sulcus involved in taste processing that lie adjacent to temporal lobe regions involved in auditory processing.

Citation:
http://www.medterms.com/script/main/art.asp?articlekey=8445
http://dictionary.sensagent.com/grapheme%E2%80%93color+synesthesia/en-en/
http://en.wikipedia.org/wiki/Ordinal_linguistic_personification
http://en.wikipedia.org/wiki/Number_form
http://undacovabear.wordpress.com/2009/02/08/sound-colour-synesthesia/
http://en.wikipedia.org/wiki/Lexical-gustatory_synesthesia