Three very mischievous old ladies are sitting on a park bench when they see an old man walk by. "Say, fella," the first lady says. "I bet we can guess your age."

The man pauses and looks at them skeptically. "Guess my age? that's impossible."

"C'mon, we'll show you," the second lady says. "First, we'll need to look up your nose." Embarrassed by the notion but wondering if the ladies truly knew something, the old man walks over and lifts his head, enabling them to look right up his nose.

"Okay, now stick one finger up your nose, one finger in your ear, cross your eyes and sing Danny Boy in a loud voice." the third lady says. The man then does so; the ladies muse for a few moments, before saying, "You are 87 years old."

"Why, that's incredible," the man gasps. "That's absolutely right! Tell me, how were you able to tell?" He had silently wondered how all of these seemingly random methods had enabled the ladies to find out his age.

The ladies reply, "We were at your birthday party."