As you can tell by this screenshot, you have a 3-D world where you can drop objects into, and then call methods and properties on them to produce movies and games.
This environment teaches them object-oriented programming as well as events and concurrency.
When you first start Alice, it walks you through a visual tutorial, explaining each of the parts and helps the student build a little movie right off the bat.
You can add the methods to conditions and loops, and is a great way to teach programming.
Additional Notes
Download Alice at www.alice.org
Start it up and walk through the tutorials.
I don't recommend bothering with version 3 initially.