8th Grade(age 14-15 or 15-16): There was a guy named Brad...one of the popular guys that was progressing the fastest through puberty...hairier legs and pits than most of the teachers and a plesant bulge. One day, we were were all playing some game that required us all to sit on top of our desks. Brad was just off to the side of me and he had his legs up on the desk, semi-crossed. Luckily, my view was right down the right leg of his shorts. Saw part of a dick, and had a good view of his hairy nutz. haha It was awesome...so much jacking to that back then.
I know there've been others, but nothin's comin' to mind at the moment. I'll post later if I think of anything.