AlphaBoxes, created by Linda Hoyt, is a strategy that can be used in many ways. It can be used before, during, or after studying a topic. If students are asked to brainstorm words they know about the topic before they begin to study it, this will activate prior knowledge and serve as a formative assessment for the teacher.
Websites for AlphaBoxes:
AlphaBoxes - PDF
A Collection of Easily-Adaptable Best Practices