Back in 70's I was working Green Bay sector at Chicago Center, which included Oshkosh. I had a Turbo Commander climbing Eastbound to FL210, and Snowbirds inbound from Toronto at FL220.
"Snowbirds, traffic 12 o'clock 20 miles opposite direction, Turbo Commander climbing to FL210, leaving FL190."
"Snowbirds, roger."
Commander 53M, traffic 12 o'clock 20 miles, head-on at FL220, eleven Tudors."
"53M, roger, but say again type."
"53M, traffic is eleven Tudors."
"Okay Chicago, what is an elev...OH WOW...THAT IS REALLY COOL."
I also worked the Pensacola area at Jax Center for 20 years, so I got to work the Blues a lot leaving for & returning from shows.
Whenever possible I would try to get them to give civil traffic a look at their tax dollars at work, and they were always glad to do it. Great fun for all involved.
One day I was in a Pitts doing aerobatic maneuvers near Wichita. Returning to the airport, I was sequenced to land on a left base for runway 19R. An America West 737 was on right base for 19R and was told to follow us. He did not have us in in sight. (No surprise, looking for a Pitts head on.) I turned on the smoke. He reported tally ho.