Somewhen around 2005 Jason Mical wrote a Pen and Paper RPG version of the Fallout games (1 and 2).
Somewhen around 2015 I adapted it to our group's style of play —never let mechanics get in the way of story.
Oh, and I tried to make it pretty. Here's the result, in PDF format.
It's an unauthorized hack-job, usually reductive, although it adds material from later games. See Appendix B for all the gory details.