A large-scale modification, Long 15, resembling a full-fledged expansion, has recently been released for Fallout: New Vegas.
Modders offer several dozen new quests (30+ are marked, and some need to be found independently) and over 200 fully voiced characters.
In addition, they add new locations to FNV for exploration, equipment, and more than 10 dungeons — from extensive railway tunnels and underground bunkers to sprawling cave systems and sewer tunnels.
The modification "Long 15 - NCR Expansion" for Fallout: New Vegas is distributed for free via Nexus Mods. The expected playtime for the mod's content is 20 hours.