Obsidian Entertainment's project director Josh Sawyer has released his own mod for Fallout: New Vegas with the aim of increasing the challenge and fixing some bugs. Yep, Sawyer was a driving force in the development of the game, so this is the real deal.
The catch is all DLC is required to use it, even the smaller ones like Courier's Stash (funnily enough, these are all dirt cheap on Steam today). Sawyer notes around 20 hours of testing went into it, and conflicts, bugs, etc. are certainly possible.
All set? Download links and info can be found on our wiki.