48 piece chalk set. I purchase a box every year and I can't imagine teaching without it handy. While I don't use it everyday having it around is so very useful.
The first time I used chalk was to teach a lesson outside. It gave the kids some fun in the sun and let them go a little wild in a big open space, especially because I have a pretty small classroom.
Another good use for sidewalk chalk is having it available when you need a quick art project, during those rare down times.
Or a quick lesson on cave drawings.
And sometimes just to let the kids have fun during recess. Sidewalk chalk in my humble opinion is a must have staple in the Elementary classroom.
FYI: I am not getting paid to advertise this is just my opinion.