My wife's cousin (cousin-in-law?) is getting married on Halloween. I am actually really looking forward to the wedding. The couple seems to be having a good time with all the possibilities for decoration, favors and the like. The bridesmaids are all wearing black and orange, the “Save the Date” was a severed finger and they were researching coffin-shaped card boxes. My wife ended up offering up my woodworking skills to make this dream a reality.
Drilling a hole in the edge of the box will allow you to mount the photoresistor so it is activated by guests putting cards into the box.
I also added a chain to keep the lid from opening all the way.