Last year my wife and I downloaded a bunch of atheist stickers from the web.Put them all together on a html page .I then went to Staples and bought some Avery sticker sheets and copied the sheet of stickers onto it.Then cut out each sticker and now have a pile of little stickers in a baggie in the car .

We put them on garbage cans,mail boxes .in bus shelters , in play grounds,on poles and street signs particularly by schools.
Especially local notice boards at laudromats and some shopping centres.You have to be a little sneaky.but the risk of being spotted is  part of the fun.

Its interesting to return to these spots to see what has happened to them.

We put one on the lid of a garbage can at the entrance to a supermarket,and every week someone rips it off,so every week we replace it with another one.Great fun.
Our favourite was just under the take-out window at MacDonalds.drive through.....Had to be real quick tho! That sticker stayed there for months until they found it.
Hopefully lots of big mac eaters got some food for thought at the same time.
Its easy to do and you feel like you are doing SOMETHING to help the advancement of sanity.
try it out.