More surprising in L-space than T-space, but some professor telling a classroom full of students something astonishing or lovely is a lost art, only to have one of the students come up after class to tell him its not lost at all - that their family still makes such things, or that they themselves (20 years old, nothing apparently unusual), know how, because they remember it. Of course memory of technique doesn't necessarily translate into muscle memory, which is frustrating.

A friend of a friend who comes to dinner and asks her hosts to adopt the baby she's expecting, because that case of flu she thought she had ...wasn't.