For me, it was Dad taking me to the Auroral Valley Tracking Station when I was 5. I was lucky enough that he was working on the NASA programme at the time but even more exciting was being able to manually move the dish out there.
I'll never forget Dad showing me the alt and azi readings on this huuuuge piece of metal with flashing lights and oscilloscope signals flaring out at me while I make the numbers match those that he had written down on some paper.
Then there was the punch-card computers and I remember the enterprising guys at the station programming 'The Enterprise vs. Kingons' into one of the oscilloscopes there. You had one green blip moving near another green blip, when they got close enough you turn the frequency pot manually and if the other green blip disappeared you successfully had launched a photon torpedo and destroyed the enemy!
Dad brought home all sorts from that station, mission patches, models, tales and anecdotes.
Got my first scope (a Tasco!) at about 8 and never looked back.