Overheard on the radio a few years ago:

N1234:
"Kalamazoo approach, student pilot N1234 five miles west."

Approach:
"Are you the red and blue Cessna 172?"

N1234:
"Yes. How did you knnow?"

Approach:
"I have color radar. N1234, go to tower 123.45."

Me:
"Kalamazoo approach, white Bonanza with black and red stripes checking in."

Approach (laughing) :
"I used to fly that 172!"

Robert Brown
via e-mail