If you enjoy these projects, then I encourage you to buy my book, Rubber Band Engineer. It's full of more awesome and original projects crafted from household hardware. You can find it wherever books are sold.
These mini projects are designed to add flexibility to your repertoire of lesson plans. Each project requires almost no preparation, can be quickly explained, and uses minimal materials. It's perfect for engaging a student who finishes his or her main project very early, or conduct several of these projects in one lesson rather than focusing on one big project.