I didn't play any sports whilst I was in school, except for during physical education classes once.
Probably best achievement I ever had was knocking up 30 runs in a game of cricket for physical education class in grade 10.
I played chess in high school, if we can consider that a sport. If there are two incidents that come to mind as "exciting".... one of them I was playing a long game (usually, when there are few games left, the players who have finished their games start to watch the ones left). A win was necessary to win that round for our division. Finally, I had got a winning position after quite a struggle, but I had a big problem - although I had a better set of pieces and a nominal win, I was running out of time on my clock. With double the time I had left I would have been just fine, but I was struggling to force the win whilst my opponent was simply putting up a rather defensive position. Eventually, I gave up my material advantage to end up with an unusual position that turned out a win for me (for those who know chess, I had four connected pawns against one rook). The chess clock buttons being pounded quickly, I wrapped up the game with about 15 seconds left on my clock.
The second incident is probably my best game ever, as it was against a very good player. How good? Well, for those who know Brisbane schools, the school was ACGS (also known as "Churchie"). The senior team of that consisted some of the best chess players of that age (or even overall) in Australia. In fact, that team went overseas to compete in some schools world chess championships, and came second. Needless to say, against every other school in the competition, they obliterated their opponents, often winning a clean 4-0, or in some cases the other team might eke out a draw or two.
They came to play us. One of their members apparently was caught in a detention, so he couldn't come, so our fourth board player won by default. My good friend as third board lost his match, as did our first board after a valiant effort (the first board player is now an international chess Grandmaster). I thought I was struggling considerably with my game as the pieces were disappearing, but he had the material advantage. As every chess player knows, the less pieces on the board, the more important an extra one. My only plan seemed to be to try and use my pieces to control as much of his territory as possible, making it as difficult as possible for him to launch an attack, whilst making it as easy as possible for me to defend my position. Eventually, my pieces were in the correct position and I managed to surround his king. Final score for our division was 2-2 - we got a draw against this team. Apparently, the news of my win rippled through a few grapevines in the other schools' chess teams.