When this question was posed to me during a senior consultation this year my brain started imagining all the possibilities. We knew it needed to be special, but it was only going to a very small gesture in the midst of her session. So I brought out the chalkboards for some fun!
"Tell me what makes him/her so special"
"What is annoying about him/her"
"What is the reason you LOVE him/her the most"
I think we succeeded!