"Mom, I was in chess club!" he said.

I barely remembered how to play chess, having eschewed the game sometime in elementary school when my dad relentlessly insisted that I master it.  Still, I sort of knew how the pieces moved.  Lucky for me, Mac knows how all the pieces move for sure.  He also gave helpful suggestions on strategy.  "This would be a good move for you," he'd say, showing me how to advance a pawn or slide a bishop.

"Why?" I asked.

"Because then," he'd say, grabbing my queen or rook, "you can go like this."  Sure enough, that would be a good move for me.

"I shouldn't have told you that," he said more than once when I pocketed a piece of his.

Another lesson: "You have to tell if the other person moves into check," he said.

"You do?" I asked.  "But that seems like that's a good way to win."

"No," Mac explained, "you have to tell."

"Why?" I asked.

"It's the rules," he said seriously.

I feel like we might do this again.  I did, in fact, triumph, but it was because Mac helped me extensively.  It was more like a lesson, and he was definitely the teacher.