I came home, put away a load of dishes, and vacuumed the whole house, with much stretching of arms under furniture and moving of bags up and down and out of the way, and throwing away bits of trash, and dusting downstairs. And then I had dinner. And then I went to take off my watch, and noticed my ring was missing.
So then there was freaking out, and disassembling the whole house. I figured the most likely thing that had happened was that it had come off when I took my biking gloves off, while my hands were still cold, so first I checked my gloves and my backpack. No ring. Then really thorough checking upstairs and downstairs and under the furniture. No ring. Vague recall of having heard rattling while vacuuming bedroom. Dissection of vacuum cleaner bag. No ring.  Check outside, to see if it fell off while I was opening the door or putting my bike away. No ring. Check backpack again. Still no ring. Check inside shoes. No ring. Disassemble entire house, including garbage cans. No ring.
Pout. Whine. Plan to call work tomorrow and see if anyone's found it there. Wonder whether CalTrain lost and found would be open now or if that should wait for the morning too.
Poke at gloves one more time, in distress that it was not there, in the logical place, the first three times I'd looked.
 However, I did find a button, a penny, and where the @#!$ bugs have been coming from. It is not fair for vermin to nest inside the cleaning tools.