While I will agree with you that some of those free energy devices out there are scam artists, some of them actually have some merit. We'll see what happens with the SPEGG on August 24th, and as for Perendev, he does have a video of the machine working:
http://www.perendev-power.com/mm_exclusiveclip.htm
There is a longer video I've seen as well with an explanation. Now the skeptical side of me says we can't see the other side of the machine, so it may be baloney, but the other side of me says it could be legit. I'd never, ever, ever throw any money at one of those machines until they're proven to be legit, yet I have a feeling we're going to see someone come up with something that defys everything we know about energy. It's only a matter of time.
$this->bbcode_second_pass_quote('MarkR', 'T')hose 'free energy' links are not very exciting. While I wish for the hypothetical 'perpetual motion' machine, I fear that we will never see one.
The 'products' showcased above are little more than scams.
The enviroenergy 'gravity' generator is nothing but a grossly overcomplicated version of a perpetual-motion idea that has been around for centuries - putting weights on one side of a rotating wheel, and then taking them off before they rise. Fine, but how do you get the weights back up again?
The perendev magnetic motor is more interesting, but permanent magnets are not a source of energy. Again, this is the latest in an innumerable list of attempts to produce a permanent magnet driven motor. Note that the only video/photos you get are of the motor starting to spin. There are no videos or demonstrations of the motor actually running and doing work (or even running at idle).
Magnets can loan you some energy - a piece of metal can be attracted to the magnet, and useful energy can be extracted from the motion. However, you need to give that energy back in order to pull the metal away from the magnet again. All this talk about 'focusing' magnetic fields is just nonsense - it would be equivalent to saying that it would be more efficient to launch a space rocket horizontally because it would experience less gravity.
Indeed, I've even seen some scams who have claimed that this energy in permanent magnets is free. It's not, it has to be added during manufacture. When a unmagnetised 'blank' is charged it takes magnetic energy from the 'charger'. If that is an electromagnet then there will be a slight increase in power consumption as the magnet charges.
There is much 'scientific' interest in 'overunity' devices - mainly on internet forums/newsgroups. So far, no one has ever demonstrated such a motor/turbine. A lot of people get confused by not understanding energy measurement.
People claiming to have demonstrated new 'electrolysis' devices often overestimate hydrogen production, by not taking into account, gas temperature and moisture content (these devices frequently produce much steam due to pitiful efficiency).
I've seen people run alternators but fail to measure 'power factor' on the output - e.g. they think the 10 A at 110 V coming from their generator is supplying 1100 W, when it might only be supplying 500 W.