Speaking to videogaming247 in London yesterday, Bethesda marketing boss Peter Hines spoke for the first time about a newly added instance involving some post apocalyptic sports fans.
There's stuff like baseball fields, just little places to come across that you would normally find if you were out exploring a DC suburb," he said.
"There's old roadside diners that you can find, and just different stuff like that. The baseball field is one we haven't talked about, but you'll find guys out in the wasteland with baseball bats that'll attack you."
Hines showed us both outdoor and "dungeon" style encounters in buildings, and confirmed that the two will be treated differently.
"The outdoor is seamless, so the entire world is non-loading: it's just one big world to explore," he said. "The indoor environments we treat separately, so whenever you enter buildings or locations you get a load screen."
The number of encounters is yet to be fixed, however, and it sounds as though there's still plenty of "fiddling" going on.
"I don't actually know how many [encounters] we've got, partially because we've been adding them and moving them around, and like, this area feels too cluttered, this area needs more stuff to do," he said.
"We came up recently with new types of random locations to put in the world, just different stuff to come across... The number's still a bit fluid, but all told there's just a ton of different locations to find and places to explore."
Fallout 3 ships for PC, PS3 and Xbox 360 this autumn.