I just came across this blog called Hip Hip Hooray! which is completely dedicated to planning kids’ parties—invitations, decorations, food, etc. Seriously, the whole thing.
And holy cow, there is some super cute stuff. Check out some of these snippets they posted:
Homemade sprinkles from Kitchen Daily
Mr. Boddington Birthday Invitations at Paperless Post
Supergirl party from Tortoise and the Haire
Cardboard box party from Hello Lucky