Zork. Text adventure I tried on a mainframe at my uncle's work in 1983.
Then in 1985 at high school I got to play it on the school IBM ATs or whatever they were (no hard drive, no mouses). I also bought my first home computer that year (Commodore Plus/4), eventually got Zork 1, 2, 3 for that plus some awful Scott Adams adventures (Pirate Adventure, Hulk etc).
Then in about 1989 or 1990 my best friend got an Amiga and we played Indiana Jones & the Last Crusade & Monkey Island 1 through. I got a PC (386) in 1991 and bought MI2, Fate of Atlantis, DOTT etc as soon as they were released in New Zealand (tended to be a few months behind the US/UK release dates back then).