As a spectator, my best memory was the first drum corps show I ever saw, the Odyssey Classic in Cerritos, CA 1980. I was in a youth band at the time and our assistant director took a bunch of us, I think to show us what we should shoot for. I thought our band was the best, but boy did I get humbled. I was blown away by some of the early corps but was told, you ain't seen nothin'. By the time Santa Clara hit the field my jaw was on the floor, and Concord... OMG. After that I made excuses for why our band wasn't that good, but by the next year's show I realized there was no way we could ever get to anything approaching that level.
As a performer, again it's the Odyssey Classic, 1982. Since so much of our corps then came from southern California, it was a second home show for us. We got standing O after standing O (even for the boring "Recuerdos") and as we marched off we were so, so hyped. When Carl said "relax" we screamed and shouted and I knew for sure that I was part of something truly excellent.