Little Computer People

Little Computer people is a life simulation game.
The game has no winning conditions, and only one setting: a sideways view of the inside of a three-story house. After a short time, an animated character will move in and occupy the house. He then goes about a daily routine, doing everyday things like cooking, watching television or reading the newspaper. Players are able to interact with this person in various ways, including furnishing the house, entering simple commands for the character to perform, playing a game of poker with him and offering presents. On occasion, the character initiates contact on his own, inviting the player to a game or writing a letter explaining his feelings and needs.

Each copy of the game generates its own unique character, so no two copies play exactly the same. The documentation that accompanied the game fully kept up the pretense of the "little people" being real, and living inside one's computer (the software merely "bringing them out"), with the player as their caretaker.

Source: Wikipedia, "Little Computer People", available under the CC-BY-SA License.