"Tours" are interactive paths through the night sky, designed to tell a story or teach a particular astronomy concept. They look like movies, but when viewed in WWT, you can pause the tour to explore regions of the sky that catch your interest, and you can click on hyperlinks throughout the tour to learn more about an object or phenomenon.
You may create a tour using the desktop version of WorldWide telescope.
Here is a screen cast of an example tour, made by Alyssa Goodman, called "Dust and Us." Download it here for the desktop client.