Synesthesia

Synesthesia: a neurotically-based condition in which stimulation of one sensory or cognitive pathway leads to automatic, involuntary experiences in a second sensory or cognitive pathway.

http://www.britannica.com/EBchecked/topic/578457/synesthesia

Grapheme-Color Synesthesia: letters or numbers appear in color 

http://www.macalester.edu/psychology/whathap/UBNRP/gcsynesthesia/diagnosis.htm

Ordinal-Linguistic Personification : numbers, days of the week and months of the year take on personalities. 

http://www.mitpressjournals.org/doi/abs/10.1162/jocn.2007.19.4.694?journalCode=jocn

Number-Form Synesthesia:  number, days of the week and or months of the year are seen imprecise locations in space

http://en.wikipedia.org/wiki/Number_form

Sound-Color Synesthesia: certain sounds trigger the viewing of colors or simple shapes

http://www.etown.edu/CETL.aspx?topic=An+fMRI+Study+of+Sound-Color+Synesthesia

Lexical-Gustatory Synesthesia: words cause specific taste sensations in the mouth. 

http://en.wikipedia.org/wiki/Lexical-gustatory_synesthesia