Heard a funny one from NorCal Approach last Saturday.

NorCal:
"Cessna 1234Z, you have traffic at 2 o'clock, about 1,000 feet below you."

1234Z:
"Roger, NorCal. I see the traffic; it's a red helicopter."

NorCal:
"O.K., but they're all green to me."

Terry Blumenthal
via e-mail