This discussion is very exciting.
I find discovery learning quite powerful. we offer a general education math course at Empire State called, "Math for the Inquiring Mind." In the course, students are provided tools for quantitative analysis, such as tutorials on using Excel, a problem-solving methodology and journaling techniques. They begin with assigned open-ended problems and move toward identifying and working toward solutions of problems they generate.
We are experimenting with a variety of peer-to-peer models and plan to do more in this area.
And, I totally agree with Maria's proposed model for curriculum. Her example reminds me of what Pearltrees helps one do- much less linear and much more learner centered. Over teh coming eyar, I'd love to find some math faculty to develop such a model for introductory-level mathematics.