My first was when I was no less than 11. I'd watched part of Waking Life, the one where they mention the lightswitch test. (Also, ironically, I slept through most of the movie)

A few weeks later I had a dream where I was in the school gym. In most of my dreams at that time I used to fuck anything that moves, but this dream was quite realistic, uncannily so. I flicked the lightswitch, nothing happened, and I continued with my perverted intentions.

I'm aware that that particular RC doesn't actually work.