Over Christmas, at a family gathering, a relative-in-law handed me a Nerf dart gun and pointed at one of my cousins, who was across the room with his back to me.
"You know you want to," she whispered with slyness.
Not being practiced with such things, I took aim anyway, and hit him squarely in the back of the head with the soft dart.
He turned around and laughed, and said I'd just "JFK'd" him.
True story. I guess more people use that term than I realized. I've heard it twice now....once from him and once from you.