Check out appinventor.org/projects. I’ve added video screencast lessons and other teaching materials to complement the original App Inventor tutorials. These are the tutorials originally written for the App Inventor site and then refined for the book App Inventor: Create your own Android Apps (which I co-authored with App Inventor creators Hal Abelson, Ellen Spertus, and Liz Looney). I’ve also added some new video tutorials not found in the book, one for an arcade shooting game (see above) and one for a note-taking app.
The video is best watched full screen HD, and each tutorial is split into 5 minute portions.