The long: For the first time, typically grownups-only DesignPhiladelphia hosts kid-friendly events. Turns out, children learn through playing with (and on) cool objects.

The short: Do you wanna build a playground?

All week long: "The Art of Active Play" series at Smith Memorial Playground begins with a grownup-oriented talk (6-8 p.m. Thursday, $10), continues with the visit of three simple yet innovative play structures - a wacky bench, a tricked-out balance beam and a mini gym, all designed and built by Philly kids working with the Community Design Collaborative as part of its Play Space initiative - temporary companions to the famous big wooden slide.

3500 Reservoir Drive, 10 a.m.-4 p.m. Thursday-Oct. 16, free, 215-765-4325,

Saturday: DesignPhiladelphia brings back busy day of building forts, domes, catapults and more with sticks and little rubber joints that work like magic and are the signature product of locally based Stick-lets. Best for ages 4 and up.

Schuylkill River Park, 25th and Spruce streets, noon-5 p.m. Saturday, free

Sunday: The Chemical Heritage Foundation invites middle-schoolers and older to tour mini labs, build hydrodynamic models and hack science games (315 Chestnut St., 1-4 p.m. Sunday, $5, free under 5, 215-925-2222,

Monday: Smith Memorial opens next (no-school) Monday for little-known national holiday Family Play Day, for BYO picnic and play midday.

11 a.m.-2 p.m. Monday, free, registration required

Basics: DesignPhiladelphia, various locations, Thursday-Oct. 16, fees vary,

Lauren McCutcheon is a features reporter who, before she became a parent, occasionally did things outside her home after dark.