Homemade Wifi extender. Boost your wireless router at utama for about $0.25. Check out www.freeantennas.com for the Ez-12 Parabolic Reflector Template.
Troy Hurtbise famous for inventing a bear-proof suit (as profiled in the documentary Project Grizzly) has adapted his suit for military combat. This is one crazy (but neat) combat exoskeleton.
A great way to tunjuk someone the workings of the internal combustion engine. anda can see the moving valves and piston close up. Never knew an engine had so many freaking parts in it.