We get this request a lot. A printed version would lose a lot of the interactivity like audio, video and jam tracks. The lessons are really designed to be used interactively, so we haven't come up with a specific way to print the lessons.
The 2 basic ways to print the lessons would be either to:
1) right-click the left frame (with the text, notation, audio/video links) and select "print"
2) alt+print screen to capture the current page and paste it to a painting program, like the paint program that comes with Windows and print from there.
We will try to create more elegant solutions in future versions.