I had a very odd moment in Fallout 3 on 360 just today. I finished putting the satellite dish thing on the Washington Monument, and didn't feel like taking the elevator back down. So I pull up fast travel just to see if it'll let me do it, and it does. With excitement, I go see the radio guy and he tells me to go to Rivet City, and gives you very good instructions on how to get to Rivet City.
Unfortunately, giving me directions is like giving glasses to a blind man, so I wander around for a while. I see the Washington monument, and wonder if maybe there's a tunnel underneath it (due to a faulty self-made waypoint). I get on the elevator and to my great surprise, it GOES DOWN (not supposed to do this, in case you don't know). At this point, I'm like "woo! I'm going underground!" I'm watching the elevator's descent...and it is plunging down through solid earth! I find this odd, but no matter...just a minor glitch in the graphics...sure there's a hole somewhere I'm going down. After descending for seriously five minutes...I'm getting upset. "What a ploy to lengthen gameplay...a five minute elevator ride. What bullshit!" I think to myself. All of a sudden, the screen flashes bright red, and I hear the sound of the doors opening and the door opens into a solid white room. I walk out, and my game freezes.
I think it happened because I fast traveled with the elevator still recorded as being on the upper floor, but I'm too lazy to confirm.