The most obvious answers for me are WoW and Aion, back when I used to play them.
For WoW it was my server first 85 Undead, server first 85 Rogue, as well as some general marathon sessions.
For Aion it was more times than I can count, with world bosses having variable spawn windows, like for instance Zapiel who had a respawn window of 26-48 hours, meaning I would camp his spawn from the 26th hour mark until he spawned, which could have taken the full 22 hours of the window (and sometimes did); And I did this for pretty much all the world bosses at one point or another.
The aim there being of course that my Legion mates were logged out at his spawn and sleeping and when he spawned I would start making phone calls to wake everyone up.
For non-MMOs though there has only been a few, Tales of Xillia was the most recent one, I played for about 18 hours straight once I hit a certain point (when Gaius came into the story), Tales of Symphonia was another. The first game I remember not being able to put down was Final Fantasy 9.
For WoW it was my server first 85 Undead, server first 85 Rogue, as well as some general marathon sessions.
For Aion it was more times than I can count, with world bosses having variable spawn windows, like for instance Zapiel who had a respawn window of 26-48 hours, meaning I would camp his spawn from the 26th hour mark until he spawned, which could have taken the full 22 hours of the window (and sometimes did); And I did this for pretty much all the world bosses at one point or another.
The aim there being of course that my Legion mates were logged out at his spawn and sleeping and when he spawned I would start making phone calls to wake everyone up.
For non-MMOs though there has only been a few, Tales of Xillia was the most recent one, I played for about 18 hours straight once I hit a certain point (when Gaius came into the story), Tales of Symphonia was another. The first game I remember not being able to put down was Final Fantasy 9.