I bought an adjustable window screen, slightly smaller than the one in the picture below, from Lowe's for $4.98.
Adjustable Window Screen from Lowe's
It's 10" in height and expands from 20" to 37". I am not going to use it as a window screen. And it would have served my purpose even if it did not expand or was smaller in size. It is going into Medha's room and will (hopefully) serve to reduce a major source of irritation - for me, not her. I was inspired by something she did every night when we were in Bombay.
Any clues how we are going to use it?