I had this AMAZING idea for a Treasure Hunter themed MMORPG (or just a normal RPG with multiplayer options)
The main premise of the game is you create a character and are drop in whatever city/area/country you choose (main areas could be like New York or Hong Kong or any other major city). You can find/get "Adventures" that begin with you finding a "Clue", like a secret map or artifact with a riddle or location. You will have skills like ancient languages or deductive reasoning that will allow you to solve these problems on these clues, that will need you to anther clue and so on. Sometimes, you will only go to a few clues in a small area, other times (in bigger Adventures) you'll travel the world, enter crypts and temples, and more to finally get major treasures that will make you rich or objects that will grant you special abilities. You can then use money to buy transportation, weapons and housing/protection.
k...please comment if you want me to explain more