[quote=Catharyn]
I've played Fallout too! I must have just missed it :'(
[/quote]

Fallout NV 
There is a legend that if you collect 50 star bottle caps and bring them to the vault there is a treasure. Its all on the link to the wiki below if you are interested
[url=http://fallout.wikia.com/wiki/Sunset_Sarsaparilla_star_bottle_cap]