Consider having maps with hidden treasures encripted with password key. If you let your way be public while the map is hidden with secret key you can claim later when the password is revealed and you verify that you had been in the hidden treasures place.
Use "Earth Cubic Spacetimestamp". The map will be a list of 22-digits cubes spacetime geolocations and each people way will be also a list of "Earth Cubic Spacetime" 22-digits cubes.
Additionaly you would have an algorithm that would shuffle and select the cubes from the map according to the latest hash so that even the ones that own the map in the first place cannot cheat on the specific cubes that will have treasures.
The tricky thing is that the map is hidden so that you are enticed to reveal your true location beforehand making it very verifiable and fair.
Also the more likely someone would pass on a specific cube the more likely that cube would be on the hidden treasure!!! This is also very important!
Please send email to
contact@coinding.com saying that you fancy this idea or something...