Computer with printer and paper (multicolored or neon is best)
decorations
HEALTHY wet dog food (e.g. beneful, science diet)
lots of chew toys
bones for the birthday pooch and his pals
paper lunch bags
medium sized CLEAN bucket (free of cleaners and bleach of coarse)
non agressive canine guests
leashes
water
peanut butter
a fenced in yard or dog park
sturdy rubber balls
Step1
Reserve a local dog park area or clean up your fenced in back yard. Clean up all of your doggy's droppings and spiff the area up. Keep all fragile or things you wouldn't want guests getting into.
Step2
Send out cute home-made invitations for your dogs b-day party. Be creative and decorate it. Go shopping and get some decorations to hang up out of reach of the dogs. Be sure you put on the invitations to call and RSVP and write "pet parents welcome" because it's best to have some of the owners at the event so they can help keep an eye on their dog. Buy a spare leash so if there is any trouble at the party you can easily give a time out. Having other owners there also allows the owners to be able to socialize.
Step3
Make some games! Besides running and romping around and playing with toys a few organized games are nice. For a bobbing for toys fill a bucket with water and toss rubber balls in. This game is easy for dogs to understand and play. FOr an activity get the wet dogfood and (with the owner's consent) make some dog cakes with it. Ask the guest's owners if their pets are vaccinated for kennel cough (dog virus, simmilar to human bronchitas, very commonly spread from dog parks and such) so no dogs get sick. HAVE FUN