There are two things that had my laughing hard that come to mind. The first one being in Fallout 3.
So, whenever I play any game really, but mostly with open world games, after I save the game with intent of turning it off to go to bed or whatever, I always have to kill like, whatever person is front of me before I do so. So in FO3, Moira Brown was this victim. After I killed her, my grenade caused her to lose everything but one arm, so I went with my combat knife and chopped at it literally like 20 times before it finally exploded off, and when it did, I turn around and am startled by Nathan standing directly behind me. And as soon as I turn around he goes "God bless the USA, and no one else!" and walks out of Crateside. My sides were destroyed.
Another thing happened in Skyrim where I was fighting off some guys, I don't remember what type of enemy, human though. But anyway, I was fighting them, and saw a bear running toward us. Being a Wood Elf, I used Command Animal on the bear, and it started attacking my enemies. So one of the guys starts fighting the bear and confidently yells "YOU CALL YOURSELF A NORD?!". I had to pause the game for like five minutes just to recover from laughing so much.
So what about you? Any funny experiences you'd like to share from Fallout, Elder scrolls, I'd love to hear them!