Tonight as I came out of the lab at sunset, I saw a bunch of these things flying around the fragrant Weigela hedge. They turn out to be hawkmoths! Probably the very cosmopolitan Macroglossum stellatarum, because they have some truly impressive speed and the coloration looks right.
The only hawkmoth I'd seen before was lab-raised Manduca sexta, and that species is like the Spruce Goose compared to these little dynamos. These buzz just like hummingbirds, and almost all my photos are just blurs. So that was my sense of scientific wonder for the day!