Bookry - iBooks Add-ons

File this one under "I never even thought that was possible, and it's awesome."Bookry is a service service that allows you to easily create iBooks add-ons that when opened in iBooks add a whole new layer of interactivity and entertainment for readers. Here is the blurb/snippet from their site:

Create your own customized HTML 5 widgets using our simple online generator then drag and drop into iBooks Author. Bookry widgets let you engage, challenge, entertain and interact with your readers like never before. Readers can play games, solve puzzles, draw pictures and save any data they enter into your widgets to the cloud. They can also share their data with others by email, Twitter, Facebook and Evernote.

Here's a sample video of 10 iBooks widgets in 90 seconds