When someone calls you while they are driving in their car because they are bored. Many times they don't have a reason to call and make pointless chit chat to get through their boredom at your expense.

Strong signs of when you were just in Cell Phone Prison is when the caller immediately ends the conversation when they arrive at their destination.

Cell Phone Prison sentences can range from minutes to hours and often you are forced to serve time by no actions of your own.
My friend calls me every day on her way home from work and ends the conversation when she pulls into her driveway. I frequently serve time in cell phone prison.
by Panther007 August 5, 2012
Get the Cell Phone Prison mug.