Springfield (Illinois) Southeast High School, Class of 1988. We were the Spartans, our colors were blue & gold.
Our football team was ridiculously bad when I was there. They won a game during the middle of the season when I was in 8th grade; didn't win another until the first game of the season my senior year. They went 0-35 across parts of four seasons.
On the other hand, our swimming & diving teams were the toast of central Illinois. I remember in college, I met a girl from Peoria (we competed against Peoria public schools), and when I told her I'd gone to Springfield Southeast, her eyes got about this big and she was all like, "Whoa. We lived in fear of your swimming & diving teams." I think they won state every year going back to like 6th grade and consecutively after that through my high school years and for years after I left.