That's a very interesting project and the type of learning I strongly support. While textbook reading, essays and exams provide the student with a basic foundation of learning, they lack the real-life experience element that is critical to entrepreneurial development.
The best projects for this type of learning are ones that expose the students to the different facets of being an entrepreneur. I would highly recommend that your students start mock businesses. You can require each student to come up with a business idea and then have the rest of the class vote on the ideas to identify the best ones in the class. Students with winning ideas would essentially become the CEOs or team leaders of the business projects. Instead of just assigning other students to work with the team leaders, I would encourage each team leader to try to solicit and pitch other students to join their team. They can even use stock options and other financial incentives to reach an agreement, as they are all important elements of building a team for any startup business.
Once the teams are assembled -- or not, if one or more team leaders choose to go it on their own -- then business plans needs to be constructed. The plans should lay the groundwork for how each team will execute their business idea. This includes developing the product or service, building a financial model and a go-to-market strategy, implementing customer service and performing administrative functions such as legal and accounting.
After the planning phase is complete, the teams can then begin taking their products or services to market. Other students in the school or in your class could be potential customers of each business concept. Instead of actual money, you can use a point system linked to academic performance awards or prizes donated by local businesses.
Let's assume that your program runs for 60 days. After the first 30 days, there should be an evaluation of each business so that the team can make improvements for the final 30 days. Each project should be graded at the end based on performance and execution.