Fallout: New California is a massive New Vegas mod that's been in development since 2013—and now it finally has a release date. It'll be out on October 23, and will offer a brand new story with 12 endings and 16,000 lines of voiced dialogue.
You'll be able to sign up to play a beta in July. The main quest, which is essentially a prequel to New Vegas, is complete and the art is finished, but the team are still working on side quests. Apparently there "aren't any" at the moment, so I imagine the finished product is not going to be packed with them. Still, I wouldn't say no to another chunky Fallout main quest.
It's set in the same world as New Vegas, but it adds new locations, some of which can be seen in the trailer above. You'll need the base game in order to play.
I'm looking forward to giving it a shot. So many of these massive projects never see the light of day, so kudos to the team for sticking with it. It'll be available on Nexus Mods, and the team are launching a Discord channel in July to coincide with the beta version.
Find out more about the project on its ModDB page.