I read this week of two lost things found again, one in an unlikely place, and the other just where it had been left.
The oldest complete Torah scroll, misplaced by a careless cataloguer, and the oldest European cookbook, lurking among the documents of the Durham Cathedral priory.
The dating of the Torah scroll is fascinating -- the scholar who found it used textual and palaeographical evidence to determine the date, and then capped it off with the carbon-14 dating.
The Durham manuscript, on the other hand, has not had a lot of details reported about it, and so I confess myself somewhat more sceptical of the dating. I'm looking forward to seeing whatever publications come from that find.