The Wikipedia entry on the saga that was "Action park"
I remember hearing about this place from some Jersey Filkers, and recall a song or two about it when it shut down in the mid 1990s. It was so exaggeratedly dangerous, it reads like an episode from "The Simpsons," like if Krusty made a water park.
Some juicy excerpts of the various rides:
Also, nonswimmers would jump off the cliffs, not fully appreciating how deep the water below was, and have to be rescued. Former employee Tom Fergus says the bottom of the pool was eventually painted white to make it easier to spot any bodies on the bottom.
Those who made it to the bottom found their progress arrested by water, which made a large splash, and then a small pool. The speed at which riders met the end resulted in many getting wedgies and enemas from the experience. Employees kept fishnets for scooping out the occasional nugget of excrement or tampon.
In the mid-1980s GAR built an enclosed water slide, not unusual for that time, and indeed the park already had several. But for this one they decided to build, at the end, a complete vertical loop of the kind more commonly associated with roller coasters. Employees have reported they were offered hundred-dollar bills to test it. "It didn't buy enough booze to drown out the memory", said Fergus.