I'm the group leader but I'm also doing these exercises with you guys.
So, here is my experience with about a half hour of Zen meditation earlier.
I meditated in my basement/exercise room. We have a large green rubber balance ball about 3 feet around, I noticed there was a white plastic disc-dot thing about 2cm in diameter on the bottom of it. The ball was sitting up on top of a wicker hamper. So, I rotated it so the dot would be at about eye level when I sit at my usual position on the other side of the room against a wall (about 7 feet away).
Anyway, I began sitting meditation and focused on my breathing. Due to my experience, it only took a minute before I felt very relaxed, a buzzing feeling all over, while I stared at the dot on the balance ball.
As I continued, my breathing began to slow. I stopped blinking as much and became absorbed in the dot and my breathing. I blinked maybe twice a minute and had to do so consciously. I began to have a large amount of neural discharges (like the flashy lights you see on your eyelids before you go to sleep). In fact, the neural discharges were so intense that the entire room- the ball, the carpet, the exercise equipment, the futon, and a dresser- became kind of blurred into one mess of color, an odd shade or brownish yellow. It was as if the individual objects lost their color and merged into each other. The dot looked less white and more blue, it also seemed to glow. I distinctly noticed auras around all the objects in the room, in the manner of a sort of vibrating haze- not colorful at all, more like a very form-fitting, defined version of heatwaves from a grill flame in the summer heat. My thoughts ceased, and I was so focused on the dot. The green of the balance ball eventually became more devoid of color, as if I were looking at it in the dark....everything became sort of gray, and the dot increased in brightness and appeared to be vibrating. After a while, I realized enough time had passed, so I kind of shook my head and detached my attention, took a deep breath, stood up and stretched. As soon as I did everything went back to normal.
That's it. Keep in mind, you guys can post your experiences more than once, if you do the exercises on different days.