Real life game

[Andail]

Lo_res_man: I'm turning to you because of the very fact that you do not live in my hometown. If I turned to people in my town, this wouldn't be as secretive anymore.
The good thing with you guys is that you're specialist in clues and puzzles, and that none of you will have the unfair advantage of being able to participate.

Vince, I've thought of two possibilites; 1) there is no prize, just an announcement on the website who's made it, or 2) there'll be no end, just new clues and puzzles.

People stumbling across harder clues further into the game will be no issue, they'll just deem themselves even luckier. If they choose to cooperate, they will share their clues on the forum, or maybe trade it for other clues. Some puzzles could be designed so that you need a number of clue-cards combined.

[Snarky]

Andail, I don't know how aware you are of precedents for this idea. You might be interested to know that this and similar things have been done many times before, presumably with varying degrees of success. Perhaps you should have a look at previous examples for inspiration and lessons. Other things you might want to check out include alternate reality games (basically the same thing, but tends to be more internet-based) as well as games like Missing: Since January/In Memoriam and LARPs (some of which resemble what you're describing).

There are also a number of campus games you can get inspiration from. MIT is famous for its puzzling community, with elaborate Easter Egg hunts and hacking (in the MIT sense) challenges. At Carnegie Mellon they have an annual daylong puzzle race called PuzzleStorm (best link I could find).

Finally, there have been a number of ubicomp experiments into using "augmented reality" devices (e.g. a cell phone with GPS locator) to overlay gameplay onto the real world, and these games often involve puzzles.