Boris Karloff, Christopher Lee, Barbara Steele, and Michael Gough? Yes, please!The Curse of the Crimson Altar, known as The Crimson Cult in the US, is an old-school Sixties horror flick that must've felt racy at the time (Nudity! Psychedelia!) and remains charming today.
"...and drugs of this group can produce the most complex hallucinations, and under their influence it is possible by hypnosis to induce the subject to perform actions he would not normally commit. (Extract from a Medical Journal)"
Any movie that opens with that quote then fades to a green-painted Barbara Steele in a golden ram's headdress presiding over a topless woman in black leather pasties whipping another woman as part of a ritual to get a man to sign his soul away... you know is a treat.
When Robert Manning (Mark Eden) realizes his brother Peter, the man in the ceremony, has been missing for ten days, he heads off to find him. Craxton Lodge in Graymarsh, however, is the center of a Witches night celebration, which involves men in sportscars trying to run down women in body stockings. It also requires young adults holding the kind of seemingly-racy-but-actually-rather-innocent orgiastic party people only have in movies... unless I'm running with entirely the wrong crowd. The party's host, Mr. Morley, is a delightfully dry and withdrawn Christopher Lee. He, along with vixen niece Eve (Virginia Wetherell) and creepy butler Michael Gough, quickly seduce Robert into staying at their large manor home.
(Delicious camp and a green chick ripe for Captain Kirk's plucking... after the break!)