The last time I was seriously hooked on a game was 1990 or so.
My sister had a game on her PC where some young alien was lost on a planet. You had to navigate the screens left-to-right and get past obstacles. The alien had suction-cup hands. I can't remember the name of the game at all, but I do recall the day I beat the last level. Maybe the name of the alien child had two Os in it?

edit-
Whoa- ok, flood of memories. I also played Duke Nukem on that machine as well as some other one where the protagonist was a whiz kid. Can't remember the name of that one. edit2- Commander Keen!

And, to be honest, I have been caught by other games more recently. Specifically the series of Hidden Expedition and Mystery Case Files from Big Fish Games (all due to my brother, bless or curse him).