So around 1990-91 I was occasionally playing some out-of-date games like Bushido or Alley Cat, then one evening I walked in on my parents, all excited, sitting in front of the computer (actually, they were just sitting in front of the monitor, but you get the point), watching the intro to Prince of Persia, and then struggling with the first level, learning their way around the game. I joined the team, we switched, I jumped some ledges, tried hard to pass the first guard without getting the sword, then let my father play again. It was his idea to pick up the sword, then we fought the guard and found some mysterious door. As I remember it, we tried to open it for hours (it was probably just minutes), searching the whole level for a clue or a switch. I had to give up, and the next day my mother told me that they finally found a switch, opened the door and entered it, but surprisingly it did not mean winning the game. It just meant getting into level two. God, that was exciting :)
Then we played some separately, but I remember that beating level 3 required the combined force of my family - well, except for my sisters, who were just spectating. In time, I was more and more commited to the game, while my parents were less and less, so they only got interested when there was something unusual, like the fat, well-fencing guard on level 6.
I don't remember how long it took me (us) to finish the game, but it was years. I must have stopped playing at several occasions (some hard riddles or duels) and gotten back to it a few months later. One of those occasions was certainly level 8, which I remember as the hardest in the whole game. I couldn't solve the final riddle, someone had to tell me to lower the sword.
I played it many times after finishing, tried to do it without killing anyone (I think I found that impossible) or with least kills. It was the first game that told a story for me, a story in which I took part. I fell in love with games and it lasted many years.