As long as you know the doggies are all healthy, vaccinated and socialized, you can have a absolute blast!! One year, we went all out for our first greyhound. There was a dog cake bakery in town, that made special birthday cakes for dogs. We had about 8 "friends" over with their humans in our back yard. We decorated the back porch and favors in Scooby Doo, have some great photos of everyone lined up wearing their party hats. (all sizes, to toy poodles to Shepard's were there) Played games, and everyone had a blast. I had scooby doo party favor bags filled with dog gourmet treats. I still look back on those pictures, and just smile with all the memories. Gracie, our first greyhound, is at the bridge now, just seeing the pictures with her and her cake makes it easier somehow.
Be warned, it was with this party it was finally agreed by all our family members that DH and I were nuts. That's okay. Our dogs are our kids. Kids can have parties, why not furchildren?