When I was a kid, I started playing a game with my friend. I was a general leading troops (from Age of Empires 1) and he would pose enemy forces that I would have to defeat. Eventually I led my force through an entire enemy kingdom and defeated their entire army in a series of conflicts. I didn't even know what roleplaying was when we did it. We played other games, like a continuation of that story (into Age of Empires 2), a standard fantasy adventure with my brother (that didn't last too long), and one game using monopoly. We each had a 10 square mile island with a base on it, we claimed properties on the Monopoly board, we made all the pieces run through one full lap and we each got money whenever the pieces landed on our property. We'd then spend that money on WWII era war machines (from various books detailing their stats and prices) and try to defeat an enemy island. We played that game for months, even though we got nowhere (I'd only earn about $5,000 per lap and even in 1940s prices, that's not much).
Years later, in middle school, I played some game called Thardferr, a text based kingdom building game. The game was garbage (once you built your second castle, your forces were split between the two and someone much stronger would instantly take it with their massively OP army before you had a chance to fill in your defenses), but their forum had a Roleplaying section. It was pretty primitive, but I had a lot of fun on there, even though looking back, I made a lot of OP Dark Elf Mary Sues (don't judge me).
I eventually took a break, but one boring summer, I wanted desperately to try my hand a RPing again, so I went to the first site that I saw, RolePlayerGuild. I went there on and off, and eventually got involved in a Roleplay that lasted for quite some time. Eventually with fears that the site might crash (among other things) we took the RP here to Iwaku. I had nothing else tying me to RPG, but I have found quite a lot of community here.
That's my story. Jeez that was long.
tl;dr Played pretend with childhood friends and stumbled into it on a crappy game forum.
EDIT: Oh yeah, and I played some DnD in college. Loved it.