As you might imagine, there is a wealth of resources on planets and the Solar System, including a number of excellent activity guides for use in the classroom. A sample of some is below:
Links
[1] http://mars.jpl.nasa.gov/
[2] http://marsed.asu.edu/stem-lesson-plans
[3] http://saturn.jpl.nasa.gov/index.cfm
[4] https://www.jpl.nasa.gov/edu/teach/tag/search/Cassini+Mission
[5] http://solarsystem.nasa.gov/ssa/home.cfm
[6] https://www.nasa.gov/mission_pages/newhorizons/main/index.html
[7] http://lunar.gsfc.nasa.gov/teacherresources.html