I have synesthesia in real life. For me, I have one of the "most common" forms, between words and colors. Specifically, I have a color-word synesthesia ("association" is <i>not</i> the right word here) between days of the week and colors. For example, Friday for me is a "medium green", Tuesday is a "light blue" and Wednesday is a sort of "soft red"... Every day has its own color, though I must mention that Saturday and Sunday are both white, though different shades. Each of these colors also has a "brightness" to it that is kind of impossible to describe in terms of regular colors, though colors seen on a computer display get close. I also have some mild synesthesia between specific letters of the alphabet (but not all of them), as well as every single-digit number. It's worth a mention that I can't think of specific instances of this synesthesia helping me remember anything, though I am pretty good with remembering numbers, and it needs to be said that I don't know what it's like <i>without</i> synesthesia, so I can't offer a comparison.<p>Very much related to this post, I can't say whether or not learning synethesia is possible. It's so hard to describe the synesthesia between words-colors, to such a degree that I'm inclined to say that any learning would be simple association, and not the synesthesia that I experience myself. For example, when I read the word "Wednesday" it's a very specific color of red with a certain bright softness about it. I "see" that color every time I hear or see <i>and then comprehend</i> the idea of Wednesday. When I see "Wednesday" as a collection of letters, there's no color, but when I summon the internal idea/concept of Wednesday, then the color is there. See how retarded I sound? That's how confusing the internal "association" is, and why I am inclined to believe that "one does not simply <i>learn</i> synesthesia"...