Starship Titanic

Starship Titanic is a computer adventure game designed by Douglas Adams and made by The Digital Village. It was released in 1998. It takes place on a starship of the same name which has undergone "Spontaneous Massive Existence Failure" and crash landed on Earth on its maiden voyage (in an allusion to the 1912 disaster involving the real-world RMS Titanic).

The player acts the part of a human (whose house the starship crashed into) who goes aboard to help fix the ship, and must solve puzzles to collect the parts of the sabotaged onboard computer, Titania. Once all the parts have been collected and inserted in the correct places, Titania comes alive and talks.

Source: Wikipedia, "Starship Titanic," available under the CC-BY-SA License.

On the website for Starship Titanic, called Starship Titanic Construction Internet, the developers created an area known as the Starlight Lines Employee Forum. This allowed free posting by anyone and rapidly developed a life of its own, becoming a freeform role-playing game in its own right, with entirely player-driven plot.