I am not so extreme. My longest single-game file is Xenoblade Chronicles for the Wii, which topped off at 115 hours. Funny, I thought I was "nearly done" around the 90-hour mark. This is followed by Fallout 3, Fire Emblem: Awakening, and Shin Megami Tensei IV, which all ran around 95 hours long. I, uh, still haven't finished New Vegas. I level-capped a long time ago.
The longest I've ever marathoned playing games, I can't even say. Most likely under 12 hours.