SwissMiss found this Unmentionables Ready Booklet for letting people know the unmentionable things in life. It caught my eye because I have always wanted to make my own version of something like this for living in NY City. I am never sure if it should be like a ticket book or stickers that I can put on the offending party. It is probably a bad idea in practice, but the booklet is cute.
Unmentionables Ready Booklet