From the ABC Weekend Special:
The Amazing Bunjee Venture was the first cartoon Hanna-Barbera's Australian division made for ABC, after working exclusively with CBS in previous years. Two kids take an unexpected test run in their father's time machine, which brings Bunjee (Frank Welker) to the then-present. Based on a children's book by Sam McMurtry.
Capt. O. G. Readmore (Welker again) is our host, with special guest co-host Bowzer (Jon Bauman, returning to his Sha Na Na persona, as he was on a break from his two game shows, The Pop 'N' Rocker Game & The Match Game/Hollywood Squares Hour). Luckily, Bowzer is kept in small doses.........
Edit, 12/2/18: I've found a video that has both chapters. The video quality isn't that great, but now you get the whole story:
As time went on, the animated entries were getting fewer & further between, as some live-action stories were moved from the Afterschool Special as its format was changed. We'll be looking at that down the road.