I got to try out one of United's DC-10 sims for free once. I was taking physics in high school and the father of one of my classmates was a DC-10 captain for United. He arranged for the whole class to give it a try. We each only got to take off, fly once around the pattern and land, but it was a blast. I think that was when I decided I wanted to be a pilot for a living.
My first time in a full flight simulator was in a TWA 747 simulator back in New York. The pilots had a good laugh when I crashed the simulator on my first landing attempt, but were pissed when I had a perfect landing my second time out!
With that I got out of the seat in a hurry, I did not want to press my luck.