Retaining mathematical knowledge is difficult for many students, especially for those who learn facts and procedures without understanding the meanings underlying the symbols and operations. Repeated practice may be necessary for developing skills but is unlikely to make conceptual ideas stick. An idea is more likely to stick if students are mathematically engaged while learning it. NCTM's Process Standards--relating to solving problems, making connections, using representations, reasoning, and communicating--are goals for fostering mathematical thinking and learning. This article presents strategies that complement the cognitive dimension of teaching and learning by capitalizing on students' innate capacity for curiosity.