I was just watching TV and saw the most ridiculous Mythbusters episode yet. They built a HHO Fuel Cell, but they botched the whole thing. They didn't add any electrolyte to the water!!!
I wonder how much they got paid to say it wouldn't work?
They did prove that a car will run if Hydrogen is inserted directly into the intake, but they didn't use a bubbler or a flashback arrestor... so they got a giant ball of fire!
If you want to find out more about HHO Fuel Cells, look up the Authorities in HHO: EletrikRide (aka The Smack!), ZeroFossilFuel, SmartScarecrow, AlmostHydrogen, sirHOAX. There are many more pros out there, but these are the first ones that come to mind.