A couple of caching-related tests of skill (and fun), that are lots of fun for spectators as well:
- Who can roll up a new log sheet to fit into a nano in the least amount of time (log-rolling).
- Take a standard assortment of swag items like you might have in an ammo can. Each participant has 30 seconds to stack the item - person with the tallest stack wins.
- Randomly select 10 cachers at the event. The contest would be who could legibly right all 10 names on a log sheet in the fastest time.
- Have a pinata filled with 35mm film canisters. One or more of them will contain geocoins. Have cachers take turns hitting the pinata (or pulling its strings) until they all fall out.
- Have a list of 10-20 cache placement scenarios (e.g. lamppost skirt, underside of mailbox). Everyone starts with the first one and has to write down what they think the star ratings should be for it. Determine the group consensus. Anyone who didn't choose that rating is out. Continue until only a few prize winners are left.
- Ahead of time, locate the coords of several cities/parks/landmarks in the area/state/US/world. Call out the coords and have people write down their guesses as to where these coords point. Closest win prizes.
- Do a mini scavenger hunt for prizes. Who has a Montana state quarter, a paperclip, or other odd item with them.
Hope this helps. Just remember to enjoy yourself as well!