I got a chuckle out of this one Monday. Maybe the humor was from voice inflection.

Unknown Pilot #1 (On Guard):
"Hey, Greg — are you up?"

Unknown Pilot #2 (On Guard) [presumably "Greg"]:
"You're on guard!"

Pilot #1:
"Really?"

Pilot #2:
"Really."

Pilot #1:
"Well, so are you!"

George Boras
via e-mail