"The Superhuman Gambit" As a former fan of comic books, this quest really caught my attention back in the day, and led to a number of really fun "Ant-man" playthroughs where I would take on a similar role using the various insect-based perks and questlines... hero or villain, those were some of the most fun times I had in the game. The quest itself was also quite good for a post-Morrowind Bethesda title. It allowed you to choose sides, influence the futures of numerous characters, and... omfg... roleplay! Although, to be fair, once you made the conscious decision to ignore the main quest, Fallout 3 had a lot of opportunities to let your imagination run wild. Well, compared to Fallout 4. Other games from other developers or even from Bethesda's past obviously do this much better, but back then they still used to give players a fair bit of freedom.