A great project that I found online where students work in groups to investigate an alternative source of energy, make inferences, evaluate the energy source, and determine benefits/drawbacks to their energy source. The 4 days are clearly laid out with day-by-day instructions and rubrics. Students create advertisements (brochure, poster, commercial, etc) and give a presentation to the class for the project.
The document "Alternative Energy Project Overview" is the original document. The document "65. Alternative Energy Project Overview" is what I modified for my class, relating the project to agriculture.