Nine is such an "almost" age. Boys that age are goofy, energetic, spunky, overconfident and easily cowed -- all at the same time. Plan a birthday party that taxes them to the limit to burn off steam, lets them get messy to keep it low-stress, has a theme so they can put the activities in context, and provides plenty of party food because -- well, they're 9-year-old boys. Invite the whole team or a few special friends to celebrate the last of the single digits with a fun-focused little boy.

Pizza, Pizza

Children in clothes cooks

Clear out your big-enough kitchen and invite a half-dozen to a baker's dozen of your 9-year-old's closest friends to make their own mini-pizzas. Hand out chef's aprons and balls of dough, set bowls of toppings in the middle of the island or work table, get an obliging pizza expert to demonstrate tossing and stretching the dough -- a guaranteed icebreaker -- and prepare for a happy mess. Park everyone around a picnic table on the patio or in the rec room and serve big baskets of popcorn, galvanized tubs of ice and cold drinks, and devil's food or tiramisu cupcakes, with a candle for the birthday boy. The chow-down can take place while the kitchen crew kicks back with kid-centric tunes or a flat-screen showing of "Star Wars" or "Iron Chef."

Get Through It

Smiling Muddy Child with Dirty Hands

Got a backyard? Get muddy and give those tough little guys a birthday party they'll never forget. An obstacle course works in warm weather -- and the bigger the backyard the better. Set up a fun run designed to be messy, challenging and exhausting. Tell everyone to wear sneakers or river sandals and bathing suits. Arriving guests get an ID tag with a number and space to print their name in waterproof marker. Split the contenders into odd and even teams and alternate starts. Challengers sprint across a dozen old tires; crawl through a refrigerator cardboard box on its side, thickly hung with wet rag strips; climb over, under and through a "web" of crisscross ropes strung between two trees or posts; run up a "staircase" of hay bales with a wide mud puddle to leap over on the other side; navigate a board "bridge" propped over a full kiddie pool. Serve Mississippi Mud Cake and medal every wet, filthy kid.

Binary Fission and Bio-cakes

Schoolboy (8-10) wearing protective goggles holding up pipette

Take your mad scientist and his mates to a hands-on science museum for some guided activities, followed by light snacks, ice cream and cake in the party room. Spring for a behind-the-scenes tour or a party-kids-only session with a museum scientist for exploring DNA, learning about critter habitats or puzzling over fitting together dinosaur bones. Plan a more casual, if more work for you, pond scum party at the local park with identifier photo books -- download pictures and print -- for each researcher, capture glass jars for specimen gathering, and a couple of strong microscopes for examining drops of pond water on a slide. Serve molecular mushroom burgers, almost-astronauts' ice cream and bottles of smart water to each guest.

Up the Wall

High angle view of a boy rock climbing

You won't be climbing the walls if you take those exuberant 9-year-olds rock climbing. No need to head for the Rockies -- just book a session at a licensed rock/wall climbing facility with a party room, let protective parents tag along to mind any space cadets, and send the lads -- and mini-Wonder Women -- skyward. A lesson and climb, with turns at backed-up belaying and scaling the heights, will rev up appetites for mountain-man mile-long subs cut into manageable lengths, sports drinks, platters of brownie bites and bowls of kettle corn, and a mountaineer-decorated sheet cake for the "King of the Hill."