According to Wikipedia, this is the definition of the "Flipped Classroom" or "Flipped Teaching"
Flip teaching is a form of blended learning which encompasses any use of Internet technology to leverage the learning in a classroom, so a teacher can spend more time interacting with students instead of lecturing. This is most commonly being done using teacher created videos that students view outside of class time. It is also known as backwards classroom, reverse instruction, flipping the classroom, and reverse teaching. 
The traditional pattern of secondary education has been to have classroom lectures, in which the teacher explains a topic, followed by homework, in which the student does exercises. In flip teaching, the student first studies the topic by himself, typically using video lessons created by the instructor or shared by another educator, such as those provided by the Khan Academy. In the classroom, the pupil then tries to apply the knowledge by solving problems and doing practical work. The role of the classroom teacher is then to tutor the student when they become stuck, rather than to impart the initial lesson. This allows time inside the class to be used for additional learning-based activities, including use of differentiated instruction and project-based learning.
Flip teaching allows more hands-on time with the instructor guiding the students, allowing them to assist the students when they are assimilating information and creating new ideas (upper end of Bloom's Taxonomy).
[Reference: http://en.wikipedia.org/wiki/Flip_teaching, September 14, 2012]
Watch this video... It explains the concept well...
"The Flipped Classroom"
"The Flipped Classroom is Born" (2007)
Classroom flipping involves students preparing for a lesson in advance using on-line technology (Youtube videos etc), then coming to class to work on the concept collaboratively with students while the teacher assists and further hones knowledge and skills... There is no "Homework"... actually there is.. but perhaps it could be called "Student Prep Work".
The class becomes far more student centered... not just teacher centered.... Traditional model is not followed...
Teachers can become more "Facilitators of learning" or "Learning Guides" and take students to another level of understanding or developing the skill.
Students know what they are studying in advance, and can work at their own pace.
Students have a preliminary understanding of what's taught, then they can spend valuable class time further developing their understanding or skills.
Students can spend more time collaborating or discussing with other students their ideas or exploring projects.
Students arrive in class, ready to apply what they learned at home.
The strategy truly embraces the philosophy that students must become Life Long Learners, and leaders in their own learning.
The Flipped model, explores the upper levels of Bloom's Taxonomy, further than traditional models of teaching.
What if students do not have access to the technology?
Extra prep time would be required of teachers... What if the teacher does not have access to the technology to prepare the lesson?
Are schools up-to-speed in helping bring this concept along... or is this a very futuristic concept?
Should we let the road blocks stop us? What can we do as "baby steps" to move forward?
* In math class, direct students to Khan Academy to a particular lesson on the site, then assign practice problems on Manga High or IXL that reinforce the concept... Perhaps easier elements of the concept.
* In Social Studies, find videos or sites that explore some of the preliminary aspects of the lesson to be taught. However, keep it interesting... not just a long documentary without the purpose explained. Assign questions or reasons why students are watching a particular video or reading about a particular concept. Students could come to class with a good understanding of the concept, then discuss in small groups while tacking a problem or assignment related to the concept.
Other ideas... Time to think... How can a school or PLN bring this concept alive? What can you start doing now?
Flipping the Classroom - The Economist
How the Flipped Classroom is Radically Changing Learning
Youtube Video, "The Flipped Classroom" http://www.youtube.com/watch?v=2H4RkudFzlc
Youtube Video, "The Flipped Classroom is Born" http://www.youtube.com/watch?v=v-y9vR7YTak&feature=relmfu