We had an estate sale at my father's house last fall. He didn't have anything really valuable. Most people were out for something cheap. Don't get me started on the Bitch and the Barcalounger.
He was a collector of information. One thing he had a lot of were maps. I think he kept every map he ever had. And the maps seemed to draw the most responses from people.
Late the first day, a family arrived as we were closing up. Well, of course we let them in. They spent quite a while in the study. I was outside, so I did not get the full experience, but their young daughter (age 10?) loved maps. If her mother had allowed, she would have taken them all and papered the walls of her room with them.
A young couple was about to move away from California. They found a 1957 map of the state, and other maps of places they had either been to or planned to visit.
Another couple with an adorable baby also had memorable finds. The husband found topographic maps of places he had hiked. Most amazingly, the wife found a large picture map of Poland (I don't think my dad even visited Poland) which had the towns her grandparents were from -- towns that didn't normally even appear on maps.