How and what did they do?
Have you ever had a candidate do something outstanding and surprise you?
I have seen a guy showing up to an interview and discuss an idea and get a potential buy-in from the Senior Partner.
He got out of the room with the Senior Partner interested in developing the idea and fund raise for that.
Outstanding sign of entrepreneurship.
In terms of something outstanding they had done, I interviewed a candidate that was an olympic triathlete before.
In terms of doing something memorable, had a candidate bring home made cookies to the interview and offer them to me. Was definitely surprising.
For the record, the first candidate got an offer and the second didn't - but this was not in any way related to either of the things referenced above.
My friend was a farmer selling the watermelons on the farmers market. He brought an iPad with the pictures of his watermelon small business, and showed them during the interview and got the offer. Of course, he was good with cases and fit.