K.A.
In our area, you can have a party at the zoo, children's museum, space center, science center, train park, amusement park, ice cream shop, ice/roller skating rink, bowling alley, Pump It Up, Build A Bear, karate studio, Michaels and more places that I can't think of right now ;-p.
You can also have a petting zoo/pony, princesses/characters, balloon artist, face painter, magician, clown/juggler, bounce house, come to your location.
You're in LA, I'm sure you have similar, if not better, party options in your area :-)
Just found this: http://voices.yahoo.com/top-10-kids-birthday-parties-plac... for the LA area.
Have fun!