Sammy Davis Jr., Zsa Zsa Gabor & Hedda Hopper in Alice in Wonderland (1966)

This Hanna Barbera production of Alice in Wonderland (subtitled What's a Nice Girl Like You Doing in a Place Like This?) is updated to contemporary suburban America. The familiar tale is changed to reflect the times beginning with Alice's (Janet Waldo) journey, which isn't down a rabbit hole, but through a television screen. She meets the requisite assortment of characters including the White Rabbit, Cheshire Cat (Davis Jr.), the Queen of Hearts (Gabor) and the Mad Hatter (Harvey Korman) who, in this version has a wife played by Hedda Hopper. Also featured are Fred Flintstone and Barney Rubble (Alan Reed and Mel Blanc) as the Talking Caterpillar.

As far as I can tell, this production of the classic story isn't available on DVD. It can be seen in full on YouTube, however. Above is part one, uploaded by OneDareLand.

Obscurity factor: 9 (not on DVD, available on YouTube, not well remembered)

Alan Reed, Mel Blanc & Harvey Korman in The Man Called Flintstone (1966)

The curious similarity between secret agent Rock Slag and Fred Flintstone is uncanny. It's this similarity that lands Fred the job of filling in for Slag when he's injured in Bedrock. His assignment is to stop the terrible Green Goose from destroying the world and that quest takes him to Paris and Rome.

MoviePosterShop.com

This full length feature is the first one starring the popular characters and, though silly, has a flashy sixties style to it. Listen for the voice of Harvey Korman as Chief Mountmore. Also featured are voice artists Janet Waldo and Paul Frees.

This is marginally well known to the general public and very well known to fans of The Flintstones and fans of cartoons in general. It's available on DVD and can be watched on Veoh. Above are the opening credits, uploaded to YouTube by alexmystyleno3.

Obscurity factor: 2 (somewhat known to the general public, on DVD and Veoh)