The birthday party circuit has left you more insecure than your days of waiting to be picked for dodgeball.Build up your party-throwing confidence with a bash by Cupcake Kids. Financier-turned-baker Jessi Walter creates customized edible extravaganzas based on a theme of your choosing — or you can opt for one she’s mastered before (Pinkalicious cupcakes, make-your-own pizza, and the Star Wars adventure are proven winners).Instead of passive party entertainment, kids mix it up making a serious mess with sprinkles, cookie mix-ins, and pastry brushes. Parties are held at select restaurants or in your home, and all of the ingredients, aprons, and goodie bags are provided.Now that’s a party that measures up.Cupcake Kids (646-789-5554 or cupcakekids.com).PLAYManhattan Movement & Arts Center Fall Kids Programs What: Choose from dance classes such as preparatory ballet, circus arts, and Afro-Brazilian martial arts. Enroll today for fall and get $50 off.Why: It’s a groove thing.When: Mon.-Dec. 13. Schedule online.Where: 248 W. 60th St., b/t Amsterdam & West End Aves. To register, call 212-787-1178.HEARToni MorrisonWhat: The Nobel and Pulitzer Prize-winning author signs copies of her new book, Peeny Butter Fudge, a tale of what really happens when Grandma is left in charge.Why: Because she is beloved.When: Wed., 6 p.m.Where: Borders, 10 Columbus Cir. (212-823-9775).DANCEGroovalooWhat: The hip-hop dancing crew presents a family-friendly look at funky freestyle dance.Why: Shake your groove thing.When: Tues.-Sept. 27. Tues. & Wed., 7:30 p.m.; Thurs. & Fri., 8 p.m.; Sat., 2 & 8 p.m.; Sun., 2 & 7:30 p.m.Where: Joyce Theatre, 175 Eighth Ave., b/t 18th & 19th Sts. Tickets at 212-242-0800.