I've read about this in an old book about Bridge (the card game). The example below is a modified version of the one used in that book.
There are 3 people (including you) sitting by the table, and every one of them gets a card. There are 2 black cards and one red card, and for some reason you want to know who has the red card. The cards are lying on the table, face down. So, how much information do you need to know who has the red card?
By definition, the amount of information (in bits