Flipped classes are a new way that classes may be offered mainly on the college level but could occur at the high school level.
With a flipped class the student is expected to watch lectures and read the material outside of class before class. Then in the class the structure is to work on labs and have discussion groups.
This is the opposite of the traditional class where the teacher presents the material in class normally by a lecture and then the students work on assignments outside of class via homework etc.
The object o doing a flipped class is that it allows the instructor more individual or small group attention instead of presenting to the whole class. Students having problems with specific material can get more individualized help in the class. It is also expected the class can get to deeper material.
Hybrid classes work well for flipping in the material is part online and part in class. In the normal hybrid class the lectures occur in the classroom and students do tests and assignments outside of class at the time of their choosing. In a flipped class they would listen to the lecture online prior to the class and then work on labs and group discussions in the classroom while still doing tests online. This allow more group project type work.
Flipped classes are one of the new tends in education. They seem to particularly work well in technology type classes.