Once a year our local Humane Society hosts a "Doggy Fun Day" and we have lots of games.

Egg and Spoon
The traditional race but you've got the egg and spoon in one hand and the dog on a leash on the other. Great for kids.

Musical Chairs
Again, the traditional one but when the music stops the hooman sits in a chair and makes the dog sit in front on them.

Howling Hounds
Which pup can howl the loudest. Granted, sometimes this doesn't work if the dogs are trained not to howl. Last year there were a couple of Bassett Hounds that won.

last but not least...

Weenie Bob
Fill up ice cream buckets half full of water and drop in 10 bits of weenie. On your mark, get set, GO...and the pup who finishes first is the winner of that "heat". Last year there were so many dogs that we had about 6 heats, then those 6 winners competed against each other...etc etc. You will also need some small containers for the little pups.

Good luck and let us know how it goes.