I do one every time we go for my wife and three daughters. I get pictures from websites online, allears is a good one and print them out. Then they have to take pictures of the items.
This year I tried something different. I walked around and took pictures of stuff the next morning before anyone got up. They had to take pictures of themselves in front of the item. I took about 20 pictures for both teams. I got to sat at the bar, have drinks and send them new things to find.