Kennywood used to have a ride where you were launched forward through a loop and then up an incline till gravity counteracted momentum. You'd then fall backwards down the incline, back through the loop, through the station, and backwards up an incline, then roll down and forward back into the station.
It was a fun ride.
https://en.wikipedia.org/wiki/Racer_75
https://www.youtube.com/watch?v=adES4jZpAHk