I'd classify myself as ambidextrous. I was naturally a left-handed person in preschool, but then in kindergarten, we had a little poll in our class much like this one, and only two other people were lefties. I regret switching now, because lefties are awesome, but I thought it was odd how unbalanced it was. Through first grade, my handwriting was pretty awful. It improved, and I can now feel more dominance in my right hand compared to my left. I still can write with my left hand; it's just a little wobbly and blockish (like a kindergartener's handwriting, hence when I switched).
When I was involved in them in fourth and fifth grade, there were some sports that I still used my left hand for, though some used my right. Like, I swung both the baseball bat and golfclub with my left hand. But I serve the volleyball, and catch the baseball with my right.
Apparently, I had a great grandfather who also trained himself to be ambidextrous; but that was because in his time, left-handedness was associated with evil, so he was forced to write with his right hand.