Even though I don't really play Fallout New Vegas any more because I lack the time, I found a good reason crack it open again. J.E. Sawyer the project director for New Vegas released a personal mod. This mod augments New Vegas in a series of ways, most importantly it makes the game harder. Not in a sense of bumping up the difficulty in the menu either. Instead it makes scavenging harder, items heal less, and XP is halved so you level up slower. This is great for me because my biggest problem with New Vegas (and Bethesda games for that matter) has always been how the game get's so easy once you get the proverbial ball rolling. Things start challenging, but very quickly you end up rolling in caps, ammo, and anything else you could possibly need. Just like that the challenge disappears, which is a real buzzkill for a game that can easily last some 80 hours.
It's not like other mods haven't already made the game harder. It's just that one released by Sawyer is as official as you can get without it being in a game patch.