This one is pretty easy for me. My first geek experience was with my neighbor, who just so happened to work for a very large computer company. I apologize, I can't remember his name, but I have never forgotten how he changed my life.
I would say it was 1978 or 1979 (somewhere around there), he introduced me to... wait for it... the TRS-80! I was hooked. I wasn't really in a position to afford one of my own, so I spent as much time as I could hanging out with him and learning what I could.
I remember getting RadioShack catalogs and drooling all over the pages displaying the latest PC's. I would go into the stores, and stand there for what seemed like ever, just playing. I wanted one of my own in a big a way. I don't know what it was, but my brain just clicked. It was my calling.
My Father took my first geek experience to the next level, by coming home one day with a Commodore VIC 20. Far cry from a TRS-80, but it was mine. And I devoured it. Soon I moved to the Commodore 64. A little more power, a lot more fun. And I was on my way. More than 30 years has passed, and I'm still pounding the keyboards.
That was my first geek experience. What was yours?