I don't really understand the concept of a "Sub Tub." From my understanding, they are actual tubs that contain activities for a substitute teacher to do. I don't really understand the concept...Don't people have daily lesson plans? When I have a sub, s/he continues to do the work that I am doing in the classroom, so it would be a lot of work to keep designing a tub of activities that align with our current units of study. Or is the tub just a fun place to leave all of the materials for the sub to find? I don't have separate "emergency plans," because my regular plans are always on my desk, and the materials are always on the counter in a designated bin. My kids know our routines, so if I ever had an emergency, the sub would just come in and teach my regular plans. I could be way off here, but it just seems like another cute trendy teacher thing...? Maybe helpful for some, but I'm confused.