Infocom was an adventure game company founded in 1979 by MIT staff and students to sell ports of their mainframe adventure game Zork (formerly known as Dungeon) to microcomputers.  Infocom was purchased by Activision in 1986.  In 1989, the Infocom offices were shut down.  Some of the Infocom employees continued to work for Activision after that, and Infocom was used as a label until 1993.  Zork games produced after that and re-releases bore the Activision label.

Adventure Games by Infocom
Made by Activision under the Infocom label. You must put an end to the powers that have destroyed Zork's Valley of the Sparrows.

Made by Activision under the Infocom label. After hearing about Earth's victory, an alien seeks Earth's help in freeing his own planet.

A curse made by Megaboz the Magnificent must be lifted by Curse Day or the empire will fall.

The god-like Implementors task you with recovering the Coconut of Quendor from the Ur-grue.

A detective must investigate an apparent suicide which is more than it seems.
A black hole mining ship investigates an anomaly that turns out to be a giant ship of unknown origin and composition.
A voice says you have passed all tests but one. Survive the horrors of the dungeon and you earn your reward.

Released in 1981. Enter the Great Underground Empire again on a quest to defeat the wizard of Frobozz.

Released in 1980. Travel through the Great Underground Empire to find the Nineteen Treasures of Zork.