I did that last year with an old railroad over-nighter bag (like the little airline bag one would get in the 1970's when booking a vacation through a travel agency, but this one for a railroad). Had the guy's name, social security #, address and phone # written inside. Did a 411.com search and found him living in Oregon (where I was living at the time and obtained the bag) - 411.com said his age was 80-90 years old. I was tempted to mail it to him, anonymously just for personal kicks, but ended up selling it after I blacked out his SS #.
A few weeks ago I picked up some 1960's yearbooks that had the original owner's name in them, heavily signed, and included a big stack of photos of her as a cheerleader, majorette and so on. A little research showed she had been the homecoming queen one year. Listed them on eBay and the original owner bought them from me! (I knew this because her name was hyphenated with married surname in addition to her unmarried name). Crazy.