Pennies are small shiny round metallic coins1 of a one cent denomination. Originally pure copper, they are now copper-plated zinc*. They feature a picture of President Abraham Lincoln on one side*, and a picture of a memorial to him on the other side*.
Although pennies start out quite shiny, through years of being passed from hand to hand, jingling in the darkness of people's pockets and purses, and languishing in jars on bureaus, pennies eventually achieve more of a dull and tarnished appearance.
If you happen to find one face up on the sidewalk, pick it up quickly, as it is considered lucky. However, if the shrine to the dead president is facing up, do not touch the penny, as this is considered extremely unlucky.
The Researcher has been informed by their local checkout girl2 that pennies are currently in shortage in the United States; so any pennies returned to circulation that you may be holding hostage would be greatly appreciated.