Free for teachers and librarians Epic! is an ebook app (it's now available on the web). There are tons and tons of free books for kids to read. It is available for purchase also for non-teachers!
Noise Control is an app available to help with crowd control. Set the sensitivity level and once the group has gone past that level for a few seconds the app will alert the group by saying "ssshhhh." We love this because it's not the teacher saying the class is too loud; it's the app!
Adventure to Fitness is a great FREE aerobic exercise website! Just log in and your class can visit the pyramids in Egypt or the Jungles in South America all while doing jumping jacks or hopping on one foot!
Cosmic Kids Yoga is online @ CosmicKidsYoga.com and also available for watching on You Tube. Great and relaxing for indoor recess or brain breaks!