This is known as the Dead Drops Project. It was designed to share files peer to peer and be anonymous offline. There is a readme.txt file that explains the project. What’s so unconventional about it is that a person can plug their laptop into a pole, wall, or building to use it.
If you live in New York, here are some places where you can find them:
87 3rd Avenue, Brooklyn, NY (Makerbot); Empire Fulton Ferry Park, Brooklyn, NY (Dumbo); 235 Bowery, NY (New Museum); Union Square, NY (Subway Station 14th St); 540 West 21st Street, NY (Eyebeam)