Inspiring applications for IPad2 in a primary school

One of the schools I support has just recieved 5 IPad 2's for the children to use within class. In short I want these to see some real use rather than just gathering dust or turning into glorified internet browsers.

So does anyone know of or can suggest any inspiring, educational, practical or just plain fun apps to enthuse our teachers and students. Paid or free apps are fine, though of course free is better.

So any suggestions?

I know that my 6 year old LOVED all the apps that I put on the college's iPad.

I only had it a fortnight with it, but put lots of good stuff on.

Just plain fun? Angry Birds (Obviously!) There is quite a bit of physics in that game, so the older kids have more to think about.