Color synesthesia has always intrigued me. I've read about people who identify musical notes by color, but I've never met anyone who has this capability. Recently I ran across the term "grapheme color synesthesia," which refers to the ability to perceive letters and numbers as colors. Wikipedia has an article
that describes this phenomenon from the point of view of several people who experience it. I always thought it would be confusing to have color sensations while reading or speaking, but most synesthetes are comfortable with it and sometimes use colors as memory prompts for names and words.