Flat
Got all ready to leave work tonight, got in my car, started driving through the parking lot, but there was something wrong. It felt like the hand brake was on, but it wasn't; finally I thought maybe something was caught on a wheel.
Pulled over, got out, looked, and it was immediately obvious: a flat tire.
As I dug the spare out of the back, I realized that I'd never changed a tire before. At least I don't think I had. But it looked relatively straightforward, and then a co-worker stopped to help (he'd just had to change one not long before) and provide good advice (like not going over 50 mph on it). I stopped at a gas station, filled the spare with air, drove home by way of El Camino (much slower than the freeway, but a lot easier to pull over to the side and deal with things if the spare went bad). Hoped to take the car to Sears Auto Center (as recommended by co-worker), but they were closed. Came home instead. Will deal with it tomorrow.