I'd hand it in to the appropriate area (police or lost and found), money and all.
Easy. Hand it in to the Police. It's the right thing to do.
I'd give the case to charity so other people can benefit!
Mwahaha! The money is mine! Finders keepers, losers weepers. Suck on that!
I'd keep the money but spend it on family and friends.
Use the money to take Loony Bob and Psychotic out on a date!
I'd hand it in to the appropriate area (police or lost and found), money and all.
Bow before the mighty Javoo!