OK, so it isn't the finest week for free-energy machines, but perhaps the boys at Steorn are just giving this category a bad name. Some seemingly free-energy concepts make sense, because they are powered not by mystical cosmic vibrations, but actual earthly ones. Scientists at the University of Southampton have created a generator that is fueled by the tremors of everyday life. It makes a trace amount of electrical current, but it's enough to power sensors and, eventually, small machines.
The trick with this generator is efficiency: Its vibrating magnets are 10 times better at generating current than other machines of this sort. The obvious use for this is in wireless sensors, that currently use batteries that need to be replaced, and therefore must be located in accessible spots. With a vibration generator like this, you can stash a sensor wherever you like. Wherever you like.
The generator may also one day be used to power a pacemaker, which would indeed be a funny twist: It would derive its power from the beating of the heart that its job is to keep on track. How's that for existentialism?