One method that seems to work to spur in class questioning is to have students write down any questions they have about the material covered in the lesson, and then collect it. Review the questions and bring them in to the next class. You can organize the questions into related topics or stepping stones, and share the questions (whether anonymously or by name - depends on the class and student) and ask students to demonstrate or discuss answers to the questions. This is a nice informal assessment of student learning, and a way to bring students into a discussion.