“You Can’t Tell Your USB from a Hole in the Wall.”

Aram Bartholl is mortaring USB drives into walls, curbs, and buildings around New York. These dead drops, as he terms them, are peer-to-peer file transfer points with true anonymity.

… The furtiveness of squeezing your laptop or mobile against a wall is rather intimate — these may be dead drops, but they’re also data glory holes.

— Glenn Fleishman @ Boing Boing

See also comments @ Slashdot.

Dead drops: “A location used to secretly pass items between two people, without requiring them to meet.” — Wikipedia

This could be useful in a multiplayer game: two players who are secretly allies use a dead drop to exchange in-game data (maps, passcodes, virtual items, in-game points, etc.). Other players try to figure out where the dead drops are located, and who is using them.

For example, in Team Fortress, Engineers would build the dead drops, and Spies would use them.

I’m guessing something like this has already been done in one or more games. If you know of any such games, please leave a comment.