Black Isle's last entry into the Fallout series tells the story of a descendent of Fallout's vault dweller who is sent out into the wasteland to retrieve a vital piece of equipment known as a GECK (Garden of Eden Creation Kit). As this device will allow survivors to create thriving communities in the wasteland, it's somewhat in demand. After adventuring far and wide, the hero returns to find the Enclave has take over his home, and he must rescue his fellow survivors. If your only experience with Fallout is Bethesda's take on the series, you should really check this one out. It's a very different type of game, but it's totally worth your time.
You can check it out on Steam.