Collaborative whiteboard application WORKS ON IPAD.
Create "boxes" to organize and share research or information students find online, or create! Great for science/social studies research
Animated videos that explain "stuff"
30 Second Voice Recorder...record your voice and it gives you a link to the recording that you can paste anywhere.
Wiki of math tools for elementary students. Organized by "generic" tools and then grade-level
Simple polling tool. You can save your poll for 3 or 7 days. No sign in or login, you just get a unique URL for your poll.