One for my baby is a Fallout: New Vegas quest in which you can gain Craig Boone as a companion.
1. Talk to Boone while he is on his night shift and exhaust all dialouge options. You should start this quest.
2. Find proof of who killed his wife. Head into the motel and wait until Jeannie May Crawford leaves. Pick the lock to her safe (easy), and take the bill of sale. (if you cannot pick the lock steal the key off Jeannie)
3. With proof in hand, exit the gift shop, make a U-turn and go down the street until you find a house. Tell Jeannie May to come with you. NOTE. (do this at night)
4. Head to the front of the dinosaur and wait for it. She will follow, put on the beret boone gave you and wait for her head to explode.
5. When it does head back to Boone and show him the bill of sale. He will comment, ask him to come with you he will ask why, you can pass a Intelligence check of 7 or tell him you kill more in pairs.
6. Congratulations, you now have Boone as a companion and have gained his Spotter perk. Which, when you use your sights, Will highlight your enemies in red. (This perk will still work even if you don't use iron sights.)