Imagine me as a five-year-old kid, lying in the upper bunkbed, staring at the ceiling in the middle of the night, mind a-whirl. (I started early with that.)
Suddenly, a thought strikes me, and I sit bolt upright.
“MOOOOMMMMM! DAAAAAAD!” I’m shouting at the top of my lungs. You’d think the bed was being invaded by bloodthirsty groin beetles. “MOOOOMMMMMMMMMMM! DAAAAAAD!”
After a couple of minutes, I hear thumping footsteps in the hallway, and my mother and father, looking distressed and quite disheveled, burst into the room, slapping the switch to turn on the light.
“What? What?” they say breathlessly, clearly expecting me to be on fire.
Instead, in all innocence, in a perfectly calm tone of voice, I take a deep breath and say this: “What do you get when you cross a vegetable with a stinging insect?”
I have a clear memory of my parents staring at me, dumbfounded, as their jaws slowly go slack.
Finally my mother says, quite deliberately, quite politely: “I don’t know. What?”
Me, proudly: “Bumble bean!”
They blink at me for a moment, then my mother says, “That’s very clever. Did you make that up?”
Me: “Yep.”
Her: “Good. Go back to sleep.”
I lay back down, still proud, and they turn off the light and leave. Nothing is ever said of it again.
It’s one of my earliest complete memories — complete, meaning it lasts more than two seconds, or more than a single image. I’m quite fond of it; I think it provides remarkable insight into the development of my adult personality. 
Somewhere, my mother has a cassette on which the four-year-old me is trying valiantly to sing a preschool song I don’t quite know all the words to, at least beyond the opening, “Abraham Lincoln, kind and true,” while my two-year-old brother, just on the cusp of being lingual, keeps interrupting with a high-pitched “EEEEEEEEEEEEEEEEE.” It’s almost magical how it’s unbearably adorable and teeth-grindingly annoying all at the same time.
