Someone posted a sign by our elevators that she had found money, and if the rightful owner could identify the amount of money, she would refund it. I talked to her about it a couple weeks later and was encouraged to hear no one came forth but the rightful owner. Made me feel good about people in general, or at least the people where I work.
It was a considerable amount of money though, about 10 times what you found. $10, I would just go spend somewhere and figure this was one of the good breaks we get in life. 

