Just finished Julia Glass's terrific new novel the Whole World Over. Saga, one of the characters, is a synesthete - with words. Here are some examples (taken from the NYT review on June 11, even tho' they fail to identify Saga as a synesthete).
According to the Times, "Saga is afflicted with ... a strange gift for visualizing words: ''The word rape -- a very dark purple, strangely royal.' ''Godfather: Red as a ruby, bottomless vibrant purplish red, a big word, impressive but airy, the silk dragon in a Chinese parade.' ''Accommodations. (A long, long train, all its cars the same dark blue.)' "
There are many more of these lovely word associations, and the book is a great summer read.