Put on your party hats! It's time for a birthday celebration you'll never forget in this fifth book in the My Weirder-est School series. A.J. is turning nine! So he's inviting all his family, friends, and favorite teachers over for a backyard birthday bash. His parents even hire a popular party planner, Mr. Marty. But what happens when Mr. Marty accidentally orders rival clowns, a bubble blower, and even a singing cowboy to entertain guests? This will be one weird party!