My first experience was when I was pre-K in the early 1970's. One afternoon, I was switching between our three UHF network channels, and I tuned into Vanna tied to the pedestal, being tortured by the rays. Needless to say, that made quite an impression on me. I finished out the episode and picked up the basics of Kirk, transporters, phasers, and the ship. Haven't looked back.
Funny, I was just thinking about that tonight before I saw this thread—how it all began for me.