Just some suggestions for you guys....

Dog/Owner look-alike contest

Costume contest

Relay races

Recall races (2 dogs are held at one side of the yard and their owners stand on the other side. When someone says "start", both owners call their dog's name and see who can get to mommy the quickest!)

"My Dog Can Do That" - REALLY fun game we play in Obedience.
Review: http://www.netpets.com/dogs/referenc...ydogcando.html
Available at http://www.doglogic.com/

chain of commands (first person has their dog do a trick or certain behavior, then the second person does that with their dog and adds a new thing. After a few turns, there will be a long chain of things the dogs do - ex: sit, play dead, roll over, fetch.... the dogs would have to go through the entire list on each turn)

Hide and seek

Tail wagging contest


Hope that might help give you guys some different ideas A lot of these we do in obediance classes so I know they work with a big group of dogs (don't require contact between dogs and can be done on leash if needed).

Hope you guys have tons of fun!