Entertaiment are things that entertain the mind. They are often based on the themes that the human brain was evolved to deeply react to and understand, like murders, backstabbing and social interactions. These themes were essential in order to survive in the world and to be able to function in it.
Entertainment can be adapted to any scale, from a single person who chooses his or her own private entertainment from an endless array of pre-recorded products; to a banquet adapted for two; to performances intended for thousands. Entertainment can also serve more serious purposes, such as ceremonial events, religious festivals, and satire for example.