This is an interesting story from BoingBoing: apparently several defense contractors have discovered coins on their person that contain tiny tracking devices. This is so James Bond.

Canadian coins containing tiny transmitters have mysteriously turned up in the pockets of at least three American contractors who visited Canada, says a branch of the U.S. Department of Defence. Security experts believe the miniature devices could be used to track the movements of defence industry personnel dealing in sensitive military technology.

It seems that these coins were used to track the contractors as they moved around and met with various people in Canada. It is unknown who planted and tracked the coins, but whoever it was, we salute you. I guess not really actually; screw you big brother [eh]!