"I stopped lecturing. [...] Instead I gave them the book and my notes to read. I ask them to read the book before coming to class, not after class, and in class, I teach by questioning so I'll talk a few minutes, [then] I'll ask a question. The students think about it and then I have them vote on the answer --- we actually use technology to do that --- so they commit to an answer and then I tell them find somebody with a different answer around you and try to convince that person.
I call this approach peer instruction because students teach each other at the same level. Rather than teacher-student it's student-student, and I as the instructor facilitate it instead of being the sage on the stage delivering wisdom."
- Eric Mazur in this video about peer instruction for active learning