Heads will roll

So I'm driving home from work this evening, and I'm at a stoplight in front of a cosmetology school. There are students coming out the door, each carrying a clear plastic bag containing three brunette mannequin heads (shades of my little sister's Quick Curl Barbie!).

The young woman at the vanguard of the group is in a hurry. In her haste, she drops her bag, spilling the contents onto the sidewalk. She instantly gets the joke, catches my eye and we start to laugh.

Is there anything so delicious as a moment of shared hilarity with a total stranger?