This is a project I do with my fifth graders for persuasive writing.
I have students "invent" a product that is not on the market and they use the attached forms to brainstorm and turn in their ideas. They then must story board their product in the form of an infomercial. Students then record their commercial on iMovie or whatever median you have to present to the class.
To add an extra element of fun I sometimes have students rate if they were persuaded to by the product or not.