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
Once given clearance to enter Little Lamplight by Mayor MacCready, the gate opens to display 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.

Big Trouble in Big Town will begin at this point unless already completed. You may choose to take Sticky with you immediately, or tell him you wish to explore Little Lamplight first. Big Town will also appear on the Map unless already discovered.

Escort
Once Sticky joins your party, you may give him weapons and/or armor (even power armor) which he will then use to defend himself.

During the trip, Sticky talks quite a bit, sometimes making up stories presumably chosen at random. His stories follow a Mad-Lib template; similar stories repeat, with only about half the words changed. You can choose to put up with it, you can tell him to shut up, or you can kill him with impunity (no Karma loss).

This quest is completed once crossing the bridge to enter Big Town.