The Departments of Mathematics and Statistics at Grand Valley State University are engaged in a project to address the mathematical preparation of all its majors, including prospective elementary and secondary mathematics teachers. In this article, we describe how the mathematics and mathematics education faculty in our mathematics department formed a partnership and worked together to change two (Modern Algebra and Discrete Structures) of the six core mathematics courses that all mathematics majors take in order to make them more relevant for prospective teachers while at the same time maintaining core content and rigor for all majors. In particular, we have used the NSF-supported K-12 curricula projects and NCTM "Standards-based" materials as a foundation to create college-level mathematics activities. By using activities that incorporate and expand upon these K-12 materials, all majors are reminded of where they have encountered core mathematical concepts in previous courses, concepts are made more relevant as they are set in real-world or concrete settings, and prospective teachers are more motivated to learn the mathematics as they see how their coursework relates to the mathematics they will teach. (Contains 1 footnote.)