Happy Birthday to You

 is an unmarked Fallout 3 quest. It can be performed independently of other quests or just prior to the side quest Big Trouble in Big Town.

Little Lamplight
When you are given clearance to enter Little Lamplight by Mayor MacCready and the gate is open you will see several child NPCs gathered around an adult NPC wearing a red birthday hat.

Sticky has just turned 18 - and at this age, it's time for him to leave the Little Lamplight. When you speak to him he tells you he wants to go to Big Town, where all the grownups go.

If you haven't already completed the quest, Big Trouble in Big Town will begin at this point. You may choose to take Sticky with you immediately or tell him you wish to explore Little Lamplight further before taking him. Big Town will also be added to your Map, if you haven't already discovered it.

Escort
Once Sticky joins your party, you may give him a weapon to defend himself. Sticky also talks quite a bit, as sometimes he'll make up a story, which this editor is assuming is chosen at random. You can choose to put up with it, or you can tell him to shut up, or kill him. Sticky is a liability, which means there is no bad consequences. His promise of Caps from his Girlfriend Red are lies. If you get him to Big Town without throttling him- Congratulations. You're a Saint.

If Red is enslaved, no caps (Needs confirmation)

This quest is completed when you cross the bridge to enter Big Town. If you talk to him you can get him to give you his party hat.