Your invitation to the ball

Kids dressed as their favorite character and caretakers can experience a majestic Saturday evening at Please Touch Museum's annual Storybook Ball.

After a red-carpet entrance, Mad Hatter will host the ball's annual book awards. There will be a musical performance by award-winning recording artist Jonathan Sprout, and kids can enjoy storytime and also dance during the Baby Loves Disco party. The night will end with a grand goodbye when guests receive gift bags.

Embark on an indoor family fitness adventure as Wells Fargo Center transforms into an exercise course Sunday at the first Relentless Challenge.

Individuals or groups can jog through the levels of the arena and climb up the stairs. You can run 10,000 feet, 250 stairs, 6 fitness challenges, and 5 floors. You can also participate in exercises led by the strength and conditioning team from Endeavor Performance.

All fitness challenge participants will receive complimentary gifts including one lower-level ticket to watch the 4 p.m. Philadelphia Wings vs. Rochester Knighthawks lacrosse game.

For those who purchase tickets on the Wings website, proceeds will go to The HEADstrong Foundations, whose mission is to improve the quality of life of families affected by blood cancer.

Cheltenham Center for the Arts will hold its annual Family Fun Day Sunday from noon to 4 p.m.

The free event will feature games, activities, and a performance by South African band Sharon Katz and the Peace Train. The band is recognized for helping Nelson Mandela's efforts to end apartheid.