Something about leading a horse to water

The girls were invited to sleep over at their friends' house last night, and when Alex went to pick them up, he chatted with the girls' mother for a few minutes.

She said the girls (aged 5, 7, 7 and 8) had gotten into their beds at a reasonable hour, and that she figured they'd talk themselves out and eventually fall asleep.

However, it got later and later and she finally went in and told them they needed to turn out the lights, which they did.

When, after a while, they still showed no signs of settling down, she went back in and told them it was time to talk in quiet voices, which they did.

When that, too, went on and on, she went in one last time and told them it was time to count sheep.

I asked Alex what happened next. Apparently, he said, Robin knows a lot of numbers.