I have science classes with labs on various days as well as rotating period for project based learning. I am able to make it so that planbook automatically grays out the days that I don't have the lab and labels the ones that I did.
Here is a screen shot of what my planbook looks like. Only two of my four classes are shown because it was just too big to fit on one screen.
What do you use for planning? Do you have any good planning methods you can share?