Once we got him calmed and put back into bed, he slept a little while and then woke up. I thought he was ready to go back to sleep, since his blinking was occasionally slow. I started just talking about anything (politics, paper vs plastic, how to make paper, etc) in a low, soft voice so he'd focus on watching my mouth and eventually fall asleep. He didn't fall asleep.
I tried talking more. I named all of the states I could think of, then all of the professional baseball teams I could think of, then all of the car manufacturers I could think of but he still didn't get drowsy. Then I thought I could start counting and he'd eventually go down. I counted out loud from 1 to 1,000 and he still didn't fall asleep and just kept watching my mouth the entire time. After that, I played the alphabet game and went through the normal alphabet, then the places alphabet, boy name alphabet, girl name alphabet, animal alphabet, and I think some others. He still didn't fall asleep.
Finally, we stumbled onto "Z" sounds that he seemed to like. He particularly liked the word "Zebedee". When I'd say it, he reacted with big smiles: