This happened when I was around 8 years old. It was summer, and the window was open in my room about 4 inches. I noticed this large shadow in the dark above me drawing closer, it was a dark oval shape. It slowly became a silver disc. And as I looked at it I felt as though it wanted to come through the window, and I thought, hm, that's a pretty big aircraft, how is it going to fit through there? And as it got closer, it got smaller. Well, that solves that problem! And it became small enough to fit through the open window!
Then I felt as though I was to join whomever was in the disc. Okay, no problem except I'm really big, and you're now really small!
Apparently that wasn't a problem, as the next instant I was inside the spaceship, and I was the same size as everyone else (whatever size that was!).
I found myself standing near the back of the disc; in front of me were 3 white chairs in a white room. The chairs were rounded and the bases of them gracefully became part of the floor. The interior walls were also white and rounded; there was nothing at the front of the craft, but I had the sense that they could see out of the entire area somehow. Two of the chairs were occupied by human boys who appeared to be my age, a third was standing next to me. I remember the boy standing next to me had brown hair and blue eyes. They had an air of excitement and expectation about them, as if they were sure I would remember who they were.
In fact I had no idea who they were, and they looked a little disappointed when they realized this. They indicated through thought that they were around 300 years old, even though they appeared to be my age. Then the boy standing next to me motioned to the back of the disc, and showed me a panel in the back wall of the disc.
Here there was a vertical panel standing perpendicular to the wall, with a something like a LED panel about 16" tall by 10" wide. In the panel were touch-sensitive floating circles. The object was to keep the circles more-or-less balanced; you move a circle, and you had to move the other circles into the same distance from each other so it all balanced out. The entire thing was a pleasing aqua-green color.
And that was all I could remember of this visit, but woke up in my bed the next morning.