First, the radial-engined motorcycle built by Jesse James. What's even cooler-but-crazier, if you read the comments on this article about an alternate take on the radial-engine concept, some guy (see the second comment) is thinking about building a motorcycle with a rotary¹ engine. Not rotary as in Wankel; rotary as in WW1 rotary aircraft engines, where the entire cylinder array spins around a fixed crankshaft.
And, for a different kind of cool just because it's such outrageous snake oil, check out the miracle hydrogen-power solution to the world's energy needs from the guy who's invented the "very unique¹ elecrolysis process" that turns H2O into the magic wonder-gas HHO. Just think, if he used his wonder-gas to run a generator to drive his electrolysis machine, he could have a perpetual motion machine!
(....Not.)
[1] Dammit! I used the word 'rotary' three times in this post. And each time, I consistently typo'd it as "rotaty". And somehow I only spotted ONE of the three typos each time I checked it........ each time I fixed one and glanced at the others to make sure I'd got them right, the others looked OK.
[2] Last I knew, the formal definition of "unique" was something like "there exists precisely one such". Does something that's "very unique" use a smaller than usual value of "one"?
