School may be winding down, but it’s too soon yet for young Boston students to lapse into summer mode. For the second year in a row, Hubbub, Boston Book Festival’s summer splinter aimed at children up to age 12, will pack Copley Square Saturday with a slate of best-selling authors and free performances sure to keep kids’ creative gears grinding.

This year’s headliners include the sketch troupe Story Pirates and “Diary of a Wimpy Kid’’ writer Jeff Kinney. While this year’s iteration boasts no singular theme, said deputy director Norah Piehl, one goal is to double down on the festival’s hands-on identity.

“The basic idea is really to inspire kids’ creativity,’’ Piehl said. “To give them really stellar examples of professionals who are doing really creative things, particularly in the fields of arts and sciences, and then give kids the opportunities to try their own hand at things.’’

In keeping with that, the festival has set up two advance outreach events in partnership with Boston Public Schools. Author Eric Velasquez will visit William Monroe Trotter Innovation School in Dorchester, while Story Pirates, known for staging adaptations of tales written by children, will collaborate with students at the Hurley School in the South End on new yarns the group will perform at the festival itself.

“They’ll be having their world premiere at Hubbub,’’ Piehl said of the new works.

Kinney, who stepped in after author Rosemary Wells had to cancel because of a family emergency, plans to honor the spirit of the festival by inspiring would-be writers with his own story. Originally trained as a cartoonist, the Plainville resident wrote the first “Wimpy Kid’’ book over the course of about six years before publishing it online.

“[My story has] lots of twists and turns, and kids seem to like to hear about it,’’ Kinney said. “I became a children’s author on accident, and I think the story of how that happened is pretty interesting.’’

Three movies and a musical later, with a half-hour special for Fox in the works, Kinney hopes the success he’s been able to achieve with “Wimpy Kid’’ while living in a small town can serve as proof to kids that success can come to anyone, anywhere.

“I think the world has really changed,’’ Kinney (pictured) said. “It’s just much easier to make a great impact no matter where you live. . . . Anybody that wants to be good at something can work hard at it and then reach billions of people.’’

A full schedule of events is up online, at hubbubfest.org.

Joe Incollingo can be reached at joe.incollingo@globe .com. Follow him on Twitter @jk_inco.