This is a game played between a team of 3 people (Ann, Bob and Chris, say), and a TV game show host. The team enters the room, and the host places a hat on each of their heads. Each hat is either red or blue at random (the host tosses a coin for each team-member to decide which colour of hat to give them). The players can see each others' hats, but no-one can see their own hat.
There are many errors that can occur when numbers are written, printed or transferred in any manner. Luckily, there are schemes in place to detect, and in some cases even correct, such errors almost immediately. Emily Dixon takes a break and discovers that codes are not just for sleuths.
Space probes, like NASA's recent Pathfinder mission to Mars, have radio transmitters of only a few watts, but have to transmit pictures and scientific data across hundreds of millions of miles without the information being completely swamped by noise. Read about how coding theory helps.