Among the kid-friendly programs are:

g Ranger-led programs – A variety of nature and history programs meant specifically for children and families are held throughout the year across Yosemite, primarily from May through September. A schedule for the various programs with their dates, times and locations, is available online.
g Youth programs – A variety of programs and camps for teenagers are offered at the national park. Among the many programs are hiking, helping field research projects, and skiing. Application must be made to participate in the programs, which are offered by NatureBridge.
For descriptions of 100-plus children’s games and activities that can be done before the hike, on the drive to the park, during a hike, and afterward, see this author’s book Hikes with Tykes: Games and Activities.
Learn more about national park day hiking trails in my Best Sights to See at America’s National Parks guidebook.