Collect the following hidden bobbleheads to gain +10 to a skill or +1 to a stat.

StatsStrength: Megaton, in Sherriff Lucas Simm's house.
Perception: Republic Of Dave, on a bookshelf on the right in the Museum of Dave.Endurance: Deathclaw Sanctuary, at the entrance on a table next to a rotting Brahmin corpse.Charisma: Vault 108, in the Cloning Lab.Intelligence: Rivet City, on Dr. Li's table in the Science Lab.Agility: Greener Pastures Disposal, in the small office covered in radiation.Luck: Arlington Cemetery North, in the basement on a shelf directly below the stairs inside the house to the north.Skills
Barter: Evergreen Mills, in back of the Market Bazaar on a shelf in the upper-right side behind the Raider Trader that does not attack.Big Guns: Fort Constantine, in the basement of the CO Quarters inside a safe in the wall.Energy Weapons: RavenholdExplosives: WKML Broadcast Station, turn on your local map. Go through the doorway to the sealed cistern and find it.Lockpick: Bethesda Ruins, in Bethesda Offices East on the top floor near the door to the bridge.Medicine: Vault 101, on your dad's desk when leaving.Melee Weapons: Dunwich Building, just before you leave the Virulent Underchambers, on the floor next to the door.Repair: Aerefu, in Evan King's house.Science: Vault 106, on a table in middle of the living quarters second level main room.Small Guns: National Guard Depot, go through the training room and offices to exit from a door to the main room. Use the power switch on the wall to your left and enter the Armory door, then search the shelves.Sneak: Yao Guai Tunnels, on top of a metal box in the Den, on the right of the map near some water.Speech: Paradise Falls, on a table inside Euology's pad (Slave Master's house).Unarmed: Rockopolis, go directly west from Casey Smith's garage. Look for tattered banners that are strung up. Use your local map to find it.