Lucky Virus

I'd like to propose a project where anyone interested in the idea would leave something of value ( i.e. $5 bill or a gift cert to a coffee shop or a toy, etc. ) in a public place with a note on it that says something like, " Smile. It's your lucky day. Please enjoy this ______."  This idea comes from someone purposely leaving a $10 bill in a library book for someone to find; I found it and gave it to a very surprised man who asked me for a quarter. My hope is to create a much larger wake of good luck in honor of the library fairy.