Adventure

Adventure, aka Colossal Cave Adventure or just Colossal Caves, is a text-based adventure game written by William Crowther and Don Woods. The game is licensed under the 2-Clause BSD License. It did not originally include any license information except a rights reservation by Don Woods as it predates modern conventions on software licensing, however in 2017 Eric S. Raymond received permission from Woods that the game may be released under that license. This applies to version 2.5, which was first released in 1995. For Raymond's port to modern C, see Open Adventure.

Adventure was the very first  interactive fiction game. In fact adventure games were named after it.