Problem Based Learning (PBL) has been around for a long time, but only recently is gaining vogue.
In problem based learning, students are presented with a complex problem which has an open ended solution. Students then solve the problem. With the right students, it is a great way to learn. With the wrong students, it blows up in your face. It is being touted as one of the solutions to our (IMO, over dramatized) educational problems, but I am skeptical.
A teacher in Australia, using PBL had a novel problem he asked his students to tackle:
Students are to plan a biological or chemical terrorist attack to take place somewhere in Australia. They must include their choice of victims, as well as their plan of attack to maximize death.
Needless to say, at least one student objected, and the assignment was rescinded. To the credit of the principal of the school, the teacher was young, and was corrected to not do it again, and is not going to be fired.