In nature, bacteria exist in and adapt to different environments by forming microbial communities called "biofilms." We propose simple, inquiry-based laboratory exercises utilizing a biofilm formation assay, which allows controlled biofilm growth. Students will be able to qualitatively assess biofilm growth via staining. Recently, we developed a biofilm assay exercise for a high school biology class and found success in increasing students' interest in biology and explaining ecological concepts. Because of this success, we feel that biofilm assay laboratory exercises would be an excellent addition to any science teacher's curriculum.