This is an interesting topic.
I started playing drums at a young age (righty). I was pretty accomplished and when I was a freshman in HS I met another fellow drummer who was left handed. We were both in orchestra and other band combos (jazz, etc). We both had our drum kits at school and I started messing around with his left handed kit. I sucked at first, but after a while I got to the point I liked playing lefty as much as righty. It also made for some interesting variations doing things I normally did right handed on a left handed kit. I improved a lot in that short amount of time compared to the previous months/years.