Since March 2011, the artist Tim Devin has been putting broadsides (small posters) up around the Boston area.
The posters come in different kind of flavors: Street Surveys, Mappy Facts or Poems by Paul Johns.
Street Surveys ask questions that people can answer by removing a slip of paper. Mappy Facts show maps of data about the Boston area - income statistics, FBI crime stats, etc. Poems by Paul Johns feature poems by Paul Johns.
If you'd like to help put posters up in Boston you can mail Tim and he will send you a print-ready file.
And of course, if you don't live in Boston or in the US, you can easily create and adapt the surveys to your own city and language.
Related: Tim Devin's I left this here for you to read