From Map-Dynamics.com - First, create user-specific geocaches that are particular for your event. Hide them throughout your venue, preferred hotels and restaurants and in cool tourist spots throughout the city.
For the “treasures” inside these geocaches, use typical trade show swag--pens, stress balls, frisbees, etc.--and watch them become sought after prizes.
The treasures are obviously less valuable than the journey, but you can still make them extremely worth pursuing. This can be achieved most easily through a grand prize. To raffle a grand prize, write numbers on each geocache. The numbers will stand count as entries in the grand prize raffle--for the greatest treasure of all.
Since each geocache has to be replaced with something of equal or greater value, attendees will have the incentive to find the treasure with the highest number for grand prize entries. You can make this profitable by having exhibitors sponsor the geocaching event.
The higher amount the sponsor gives, the greater number of entries into the grand prize raffle--and thus, the more sought-after treasure.
In addition to user-specific geocaches, attendees can also find geocaches that are already placed within the city. Locate these geocaches and assign prizes to attendees who seek out these treasures and sign the log book. Whether the prizes are hotel deals, restaurant and retail coupons, or entries into the grand prize raffle, the likely outcome remains the same. Geocaching presents a great way to get attendees to experience the city and to make your trade show both memorable and remarkable.
For simple instructions on geocaching, check out http://www.youtube.com/watch?v=-4VFeYZTTYs&feature=player_embedded
Via Gary Hayes