I was on my way home from CID to BWI by way of ORD and nabbed a handy jump seat on a UAL 72 along with a UPS guy who was on his way home too. It was a full boat so both of us were stuck in the cockpit and, of course, the 72 had a delay for a deferral of some sort.
These were the olden days before 9-11 when the captain would often offer folks in the back a chance come up and see the flight deck- especially during a delay. Sure enough here comes a smiling dad and his little son. I avoided jokes about gladiators as the captain showed the dad and kid, both of whom had zero aviation knowing, things in the cockpit.
For no good reason at all the father quipped to his little boy,
"Ask 'em what zulu time it is."
It was probably the only actual "aviation" term that the guy knew and the kid just stood there quietly with wide eyes trying to soak in all of the lights, dials and handles while daddy just went back to chatting with the captain and FO.
I could not resist. Glancing at my watch I saw that my zulu hack showed 20:18.
Leaning over I whispered in the kid's ear,
"Tell 'em it's 20:18 zulu."
Without hesitation the little guy blurted out,
"It's 20:18 zulu daddy!"
The dad looked down at his grinning son with some astonishment as I sat there casually looking out the window. Meanwhile the FE looked at his watch and said,
"He's right, it is 20:18 zulu!"
Just about then the UAL line mechanic appeared in the cockpit door with our paperwork and totally puzzled father took his apparently born aviator son and went back to their seats. The UPS guy leaned over as said to me,
"Oh, that was slick."
On the flight to BWI we let the crew in on what I did and we all had a good giggle, especially considering the look on that dad's face.
That was long, long ago and I wonder what that kid's doin' today.