Works in any museum. Hand them the list, tell them to find their favorite, and meet back at the entrance.
Something older than your grandparents
Something you could fit in your pocket
Something bigger than a car
Something that would be terrifying in real life
Something that made you feel something (any feeling)
Something you want to learn more about
Something in a language you can't read
A portrait of a face that reminds you of someone
Something that seems out of place
Your single favorite thing in this museum
The follow-up conversation is the point. "Why was that one your favorite?" is gold.