Biggest audio hoaxes

Often when people discuss audio, they talk about "snake oil" or "hoaxes."

It's pretty typical to use the term hoax as a tactic against another who disagrees with one, or holds an unusual opinion or vouches for something which has not been verified. That's not what I mean by a "hoax." 

By "hoax" I mean an audio product or claim which has been pretty definitively disproved. Maybe not to everyone's satisfaction, but to common consensus.

So -- with that definition of hoax in mind, what are some of the biggest audiophile hoaxes you've heard of?
MC, that does appear to be a coherent explanation from Geoff.  He wasn't always just full of (admittedly pretty funny) snark.  Do you get to pick the hat you eat?
All those scams pale in comparison with by far with the two greatest perpetrated by Bose. #1 is the Bose 901 direct/ reflecting bogosity, all versions.
#2 are Bose noise canceling headphones. In this case it's not that the technolgy doesn't work, it does, but that the R&D was paid for by you, the US taxpayer, to the tune of over $100 M dollars. Bose received a DoD contract to develop noise canceling technology, and after failing to deliver any usable device or technology the DoD pulled the plug. The $100M written off.

Years later, a new engineer happened across the basic research, took on the project anew, and the Bose noise canceling headphones were shortly on the market, based on the original taxpayer funded research. Bose has never reimbursed the government a single dime. Your tax dollars at work. 
I would love to have some kind of noise cancelling system for a listening room. A bit pie in the sky, but people have spent a lot for what seems a lot less plausible.