My students always come up with ones that I don't think of, which is the beauty of doing math talks. All students see that there are multiple ways of getting to an answer. Regardless of whether you are the top student or one who is struggling, you found a way and can learn from others. If you are not familiar with math talks, you might want to check out Jo Boaler's work and the YouCubed website.
As I didn't know quite how far my students would get in my absence yesterday, I left some really boring worksheets for them to practice calculating surface area and volume of prisms and cylinders. As much as I like to keep my students engaged and don't think these worksheets will necessarily do that, I think some will need the practice and my substitute teacher will need something concrete for them to work on. Working with triangular prisms is especially tricky for many of my students so this will hopefully help them work out the kinks in their thinking.
I also left them this 3-act to work on.