Rumspringa

Who uses it: the Amish
What it means: in Pennsylvania Dutch, it means "running around;" the period of time after teenagers turn 16, when they are sent out into the world to behave recklessly before choosing whether to embrace the Amish lifestyle as adults.
How you can use it: To describe a period of irresponsible behavior.

No rumspringa for me last night, although my friends and I turned around at The Great Lost Bear to see a table full of young men who could not possibly have been 21.

"That's the thing about getting older," I said, "Everybody looks like a baby to me."

"No, they look twelve," said Jen, who is several years younger than I am. "And she didn't even card them."

"That one boy has never shaved, ever in his whole life," I said, about an angelic-looking youth in the corner.

Today's a Morrissey kind of Sunday -- silent and gray, and too wet to play field hockey. It would be overstating it to say "How dearly I wish I was not here," but maybe I'll go to the movies this afternoon.