Developing mathematical talent in our students should be of primary consideration in education today as nations respond to the challenges of economic crises and ever-changing technological advances. This paper describes two U.S. federally funded curriculum projects, Project M[superscript 3], Mentoring Mathematical Minds, and Project M[superscript 2], Mentoring Young Mathematicians for students ages 5 through 12. These projects foster in-depth understanding of advanced mathematical concepts by challenging and motivating students to solve and discuss high-level problems in a fashion similar to practicing mathematicians. The curricula have undergone national field tests with proven research results showing significant achievement gains for students studying the curricula over a comparison group of like-ability students. This paper outlines the philosophy behind each program and its connection to the literature and best practices in the fields of gifted education and mathematics education. Next, specific instructional strategies integral to both curricula are outlined. These strategies help teachers establish a community of learners that promotes rich discussions as a platform for posing and solving interesting problems, constructing viable arguments, and defending as well as critiquing solutions. Finally, strategies to help young student mathematicians develop clear and logical written justifications for their mathematical reasoning and share their creative insights are described. (Contains 3 figures.)