The Dummy Killer!

The Dummy Killer Rube Goldberg machine is a great way owners to destroy those pesky mobs of dummies knocking on your door. This contraption runs quite well and has a wheel and axle subsystem to start it off, then a pulley, followed by a lever which shoots a rocket at your computer mouse, setting off the final part of the machine. In the final two stages, a lever is pushed, causing a giant door to open. This lets a big ball roll down an inclined plain, hitting another smaller ball. The small ball rolls into a set of giant dominoes, getting bigger as it goes along, then when the final domino comes crashing down, it crushes the entire mob of dummies, saving your doorstep from those pesky little buggers once again.

Materials used: LEGO, string, metal, a 9V cell battery, an ancient computer mouse, and a bunch of virtual bocks.

Overall it ran very smoothly, and didn't have many problems to fix.