Got a call from the people who bought our old car. Turns out that both Tracy and I were supposed to sign the title when we completed the sale, since the car was in both of our names. This was unclear, since there was only one line for signatures for both parties, so we just thought it would be fine for one of us to sign it. And nothing had come up around this when it was time for us to turn our paperwork in.
So the buyers came by this afternoon, for all of the ten seconds it took for Tracy to sign the title (they'd gone to register the car and they got turned down because of the missing signature). (While typing this, I realize that we should have photocopied the newly signed version. Oh, well.)
I guess it's been about a full two weeks without the car. There have been a few times lately where it would have been really handy to have it, but even so, I haven't missed it.