Have your group form a line.
Provide a written message or sentence to the first person in the line. This person then whispers the message to the next person in the line and so on, until the last player is reached. This person then announces the message to the whole group.
Inevitably, the message has morphed as people miss-hear or miss-translate the message and is often drastically different from the original message!
This game leads well into a discussion on communication and gossip.