One that stands out in my mind was when Rocko and Heffer go to a ranch and a ranch-hand hooks up the cow milking machine, and it's implied (less than subtly) that Heffer got sucked off by it. I was amazed, even at 14, that that got onto Nickolodeon
Great show though.
Standout episodes to me (looked up episode names, not good enough to remember the names offhan):
"Jet Scream" - The RML take on flying
"Popcorn Pandemonium" - The RML take on movie-going (excellent trailer parodies)
"To Heck and Back" - Heffer goes to hell
"Uniform Behavior" - Heffer becomes a night-watchman
"Born to Spawn" - Filbert gets called back to his home island, but is hesitant to return
"Cruisin'" - Rocko and Heffer go on seniors cruise with Grampa Wolf and a trip through the Bermuda triangle makes the seniors young and the youngins old