I'm generally not a fan of kids. If I wasn't an EEVBlog fan, I'd probably find this video annoying. To perhaps add insult to injury, I like cats. Maybe I would sympathize with their plans to take over the world.
At around 29 mark (showing the back side of the home made plasma board) I actually thought the drawn line on the top left part of the board was a long crack. :/
The plasma speaker reminds me of a different but similar technology, the flame speaker, of 1968 vintage. Instead of using a high voltage to generate a plasma arc to be able to whack some electrons through the air, they were using a acetylene flame "seeded", as they called it, with salts. The addition of salt got the impedance down from ~1M to 2.5k. Brilliant. Someone ought to try and build one. Comes with a simple schematic. All you need is 500V DC supply, audio amplifier, 25:1 transformer, suitable electrodes and an acetylene torch.
http://www.swtpc.com/mholley/PopularElectronics/May1968/Flame_Amplification.htmAlso attached, scans from a Swedish science magazine from about the same time on the same topic.
As for the choice of audio clips to try with the device.
"Retarded product of the week" No!
"Flying pigs" Potentially, if you don't know what you're listening to.
"I smell bullshit!" Well, I hear that ozone can remove rancid odors, including the smell of cattle manure.