For all my complaints about the nonsense that percolates among Unitarian Universalists (and church people generally), I have always loved the Wayside Community Pulpit. These posters, printed with thoughtful and pithy quotations, were the perfect complement to the automobile age. They were Twitter (or Identi.ca) before the age of the Internet, much less microblogging. I wrote about them before, with a period picture here.
The UUA has a tidy history of the Wayside Community Pulpit, but alas they are no longer being printed; instead you may download the posters as a PDF and have them printed locally. (In a pinch, you can print them as "tiles" on smaller-format paper and reassemble them.) This, I think, is a good thing. Having worked in publication production and sales, I can imagine they were expensive to produce and ship and difficult to make them pay since storage and damage took an unrecoverable toll. And software and print shops make that effort futile. Indeed, I hope some enterprising sorts come up with their own. Here's my own waggish effort (PDF); it took less than fifteen minutes.