This is a theory explaining the fallout universe from the perspective of the main protagonists of most fallout games...
The theory goes that all the protagonists from the fallout series are the same person in a vault tech simulation. In fallout one they are testing how people would act if their vault depended on them and what they would do to help them. After the quest was complete they told him that he was exiled seeing what his reaction would be, after being in the simulation so long all of his memories had been lost making him believe it was real life. To stop him going insane when his character died they put him in a different perspective his son the chosen one and kept running the simulation. The second test fallout 2 was testing what the survivors reaction to the remaining government forces. After fallout 2 to stop you from going insane when the chosen one died they moved you to another perspective, the warrior from fallout tactics to see what you would do serving under a new government force. After fallout tactics they did the same thing again and moved you into the perspective of the lone wanderer from fallout 3. The test this time was to see what you would choose for the wasteland to side with the enclave or the brother hood of steel. though the simulator suffered many glitches when in the dunwich building as some of your memories of the building itself are momentarily shown. Then finally in fallout new vegas they test yet another perspective testing what fate you would decide for the Hoover dam.
As far as my theory goes you are still in the simulation waiting for fallout 4. Another little "Easter egg" is in the description of the game from xbox 360 store says vault tech your first choice in post-apocalyptic simulation. I did not take this from any other page or website i just made it up in my head using the " evidence " i had. What do you think...