Harkness Methoda teaching and learning method involving students seated in a large, oval shape in order to discuss ideas in an encouraging, open-minded environment with only occasional or minimal teacher intervention. source ; further reading

Problem-Based Learning (PBL)a student-centered pedagogy in which students learn about a subject through the experience of solving an open-ended problem. source 

Hands-on Learninglearning characterized by active personal participation in a learning activity; the activity is individual and direct. In American education it is assumed that the activity is beyond listening, writing, and reading. In mathematics education it typically involves manipulatives, and/or measuring tools. source