Finally, I decided to try my hand at darning. What harm could it do? and I might learn something new.
First, I found a ball (no darning eggs here) and some yarn (that, of course, doesn't match).
Then (following directions found on the 'net), I sewed around the hole with a running stitch. Next I sewed vertical long sts to cover the hole.
Finally, I wove the yarn vertically through the long sts and ta-da! One sock, ready to wear again!