Turns out

it was a bad Oxygen Sensor. Several somewhat hard-earned bucks later, the car will pass inspection when the next one comes up in a month or so. I have no idea if I could've replaced it, but since I probably couldn't, I might as well pay the guy on the corner.

Oh, and oldest completely faded out at the museum - perfectly fine one minute, now she's upstairs asleep. She just got off the juice from the strep, too. Maybe it didn't work.

Sigh.