Free iPad Apps for Elementary Students

This is still a work in progress, but here is my list so far. Please feel free to add to it:
https://spreadsheets.google.com/ccc?key=0Ai5deysPpXejdFNuemJURDdoa3VWbUNDYVliOGw5T2c&hl=en&authkey=CIersPQH