Bethesda just announced a mobile game titled Fallout Shelter, allowing you to create and manage your own Fallout Vault. Tasked with keeping dwellers happy, safe, and propagating.
Fallout Shelter will release free, and will not have any pay wall timers, internet connection, and no wait times for building. There are some in-app-purchases available, but not required to play.
It is available now on the apple App Store for iPhone, and was developed with help from Apple.