I once found a diary of a child in our stone foundation. It was up along a beam tucked away near a crawlspace. It told of egg collecting, weather and friends for life. The pet cow and walking to school together was the best. Took place in the 1905-1907 era. It was the grandfathers of the folks I bought the house from.
Other than that, plenty of old beer cans an nut cache's from the local mouse house.