The Signs of Life blog is a community art project documenting unusual signs from around the world. Most of the signs are wacky or contradictory (one of my favorites: On this spot in 1765 nothing happened), but others are touching (I want to hold your hand). Often the signs show cultural divides, or provide evidence of unexpected problems that necessitated signs (see: caution: frogs may be HOT!).
The best part of the blog is that you can submit your own signs. Maybe it's time to submit Stop Hammer Time.