Light bulbs (what them in theatre call "lamps") are annoying. Turns out the base in my ceiling fans are "intermediate" base, which is a size that is all but extinct. Here's a chart of light-bulb bases.
Rather than deal with that nonsense I got some E17 to E12 adapters. I suppose I could have gotten E17 to medium (E26) adapters. But I didn't. So there.