When I was a freshman in high school, I figured out that I'm ambidextrous. I grew up writing with my left hand, but in the Era of Erasable Pens I routinely came home with blue residue all over my hand. After essay tests, it ran halfway up my arm. I looked like I'd just bloodied a Smurf.
The pivotal moment came when I sprained my left wrist at basketball practice three days before my huge essay test on Greek society. My writing hand was wrapped up tight (like a toiger) and useless, so I had to write the whole damn thing with my right hand. My teacher was sympathetic, so he gave me as much time as I needed to finish it. It took almost two hours, and by the time I was done my handwriting was looking a lot better than when it started. Plus, no blue crap!
Since then I've learned to do cool stuff, like switch-hit and throw a 30-mph fastball with my weak hand. But what's really got me fascinated is the whole left-brain, right-brain conundrum. I still draw with my left hand, for example, and feel very creative; when I do my taxes, I use my right hand and feel like a complete numberwonk.
Then there's the issue of seeing both sides of both sides of every issue. I usually have a devil of a time making a decision. I like to dither and muse and basically put stuff off. Lucky for me, I can't decide if that's a problem.