Flatworld Knowledge provides textbooks online for free. This website also has apps so you can view your textbooks on your iPad or iPhone. They also have a way to view your textbooks offline just in case you don't have internet.
Google's database for aspiring and professional app developers alike, this site contains loads of useful tools that google has made available for anyone to use in their API. They even give you API coding tutorials and provide you with the source code to include Google API's in your API!
It is a app that lets you organize you things, in charts, and lets you give them different fonts and styles. It also lets you put notes on different sheets and annotate it.
Aris is an open source platform for creating and playing mobile games, developing tours and telling interactive stories. " Using GPS and QR Codes, ARIS players experience
a hybrid world of virtual interactive characters, items, and media placed in physical space."
LiveMinutes is a great productivity tool which combines chat rooms, video meetings, document editing across multiple formats including Microsoft Office, PDF's and many more. Also it can sync with your to-do list on evernote. The site even has an app which will send you notifications on workspace activity and you can even video conference from your phone.