In 1994, when I was riding road on an Epic Allez and dirt on an S-works, Popular Mechanics showed us the Skyway, where
“human-powered vehicles would course through conduits at 35MPH.”
Also see this bike-by-wire system from Martin Angelov.
My bikes, the music I listen to, and hairdo has changed over the years.
These ideas? Still promises for tomorrow. Will say that recumbent roller coaster does look fun. Zipping between campuses at Google.