Busted!
This evening as I was riding my fixie, I noticed that my rear wheel was really wobbly. I thought someone had stepped on my wheel or something, but it turned out that I broke a spoke without even noticing it. This doesn't come as much of a surprise since the twenty-year-old spokes are pretty oxidized. I managed to limp home, and I've put the bike in the shed until I can get a new spoke.
I guess I'll be saving up for a new wheel. I've thought about re-lacing it, but I don't have a truing stand, and the terrible wheel isn't really worth it.
Sigh. It's sad to be without the fixie.