Well, I guess I should post in this thread :)
There are too many to name, but here's one close to my heart.
When I was a freshman in high school, I got into a bit of an escalating trash talk war with Lou, a cast mate in the school's production of Damn Yankees. He considered himself the best GoldenEye 007 player around. I thought the same of myself. We went back and forth, finally deciding to settle it in a public forum.
Closing night, everyone assembled at a local house for the after-party. And the battle for champion of the universe began. To start, it was a four-person match: me, Lou, and two others. Lou and I placed second and first, respectively. Then, there were two. In a grueling match that pushed both of us to the limits , I finally emerged the victor. It was such a fun night, with a crowd of people cheering us on.
And Lou's one of my best friends today - 17 years later :)