Space Quest I: The Sarien Encounter (1986)
This was the first Space Quest to come out. It sported awesome (for the time) graphics that had a 3-d sprite walking around, trying to save the universe from a terrible race of aliens named Sariens, hence the name "The Sarien Encounter". It introduces the character of Roger, a slightly stupid, fool-hearted janitor that saves the universe from the evil Sariens. It had a wonderful story line and funny dialogue that probably sold it out and made people want plenty of sequels to go along with this one.