Synesthesia

Synesthesia (from the Wikipedia article) is condition where the brain "mixes up" information streams from two (or more!) senses ( a simplified definition). It only affects a small percentage of the population (around 4%). Most commonly, synesthetes connect graphemes (letters and numbers) with colors. The letter 'A' might be red, while the letter 'Q' might be purple. Others might connect music and color - they will literally feel different colors depending on the kind of music.
A more rare type is called number form synesthesia. People who exhibit this form may, for example, have detailed maps associated with things like numbers, time, or anything linear. These 'maps' may even occupy a definite geographical location (from the brain's point of view). N.F.S may result from "cross-activation" between regions of the parietal lobe that are involved in numerical cognition and spatial cognition.
The reason I am going on about this is simply, I believe I have Number Form Synesthesia (!). As long as I can recall, whenever I think of numbers, I can see a definite visual map, like a number line, with each number in a definite physical location, always the same. The mental map will rotate and track along the twisting number line to keep whatever number I am thinking of centered. For example, the number line starts at 0 (negative numbers are represented, but they are more of a shooting line off to the left, going on forever) and sweeps around through 180 in front of me up through the number 10. If I start to think of higher numbers, the line rotates as the angle increases, so 11-20 are in essence behind me, but are rotated into view when I think of them. When the numbers reach beyond 20, things get ever weirder - the number line begins to spiral away in ever increasing circles, with little wiggles at each decade number (30, 40, 50, 60, etc). 100 is a special number - the line no longer spirals but extends to the right, still with wiggles at the 10s and (if I am thinking of higher numbers) at the 100s. Does this sound bizarre yet? Cuz it gets weirder.
I also see time as a map - the hours of the day are (surprise) a clock face! Not that weird, I guess, and I suspect alot of people may use this image as well. After all, we all see clocks every day. But beyond hours - the days of the week have their own mental map for me. Imagine a smiley face, very broad smile, with the eyes just above and VERY close to the smile. Monday begins the smile on the left, followed by Tuesday (a little further down and to the right), and then Wednesday, which is at the trough (deepest part) of the smile. Thursday and Friday complete the curve of the smile. Saturday and Sunday are completely disconnected from the smile days - they rest above the curve (they are the eyes of the smiley face - I'm not seeing a smiley face, that's just the best description I can think of).
The months even have their own map - each with its own definite location relative to the others. Even the years themselves are arranged in a weird linear map. To me, the 1990's have a almost physical location (well, not really physical in the real sense, but the mental map is very real to me).
I've never really thought about it much - its not something I ever mentioned, simply because it is so basic I never thought about it (like walking or breathing - it just happens, unless something goes REALLY wrong). I was perusing Wikipedia, something I do when I'm bored, and came across the synesthesia article. I almost jumped out of my chair when I read the number form section - I kept thinking "THAT'S ME!! THAT'S ME!!!! " Not that it makes a big difference - synesthesia isn't a terminal condition, nor is it a disease at all. I just think it is wonderful to discover something about myself which has been part of me for 30 odd years, but not something I ever really thought about before. I AM A SYNESTHETE (well, from reading the article, I am very very sure I am, but that's not a professional diagnosis). I would really like to be able to hear color in music though - that would be awesome.