If someone assembled a bunch of smart and self-aware old films about sex ... films that stood the test of time ... who'd watch? Camp ("failed serious," as Sontag said), corn, dated aesthetics and downright weirdness are much funnier. But such artifacts, too, tell us about their times. Take "What's The World Coming To," a silent-era Hal Roach slapstick set "100 years in the future," where men and women are more alike, complete with blushing groom and butch matron of honor. Must be some zeitgeist in there somewhere. San Francisco-based archivist and filmmaker Stephen Parr brings "World" and more to the Jefferson Presents ... screening series in his The Subject Is Sex, Vol. 2. I missed Vol. 1, but this 90-minute anthology is generally hilarious, often mind-bending. Most of the 27 selections date from the 1940s through the '70s. There's "Sadie the Sunbather," a stag film whose male narration boils down to "them gals is dumb, but they sure are purty." A lengthy promo touts "Nylon: the goddess fabric" ("awaken your senses to the drama of Tricot"); another pimps Frederick's of Hollywood ("Does Frederick's treat women as sex objects? Of course. That's the whole point!"). Plus: trailers for exploitation flick Black Mama/White Mama and American Dreamer, a portrait of naked, gun-toting hippie Dennis Hopper that Hopper himself suppressed; two slices of gay beefcake (both amateur ... one creepier, if with prettier boys); and a 1955 cartoon featuring Woody Woodpecker in drag. Shreds of hipness abide. But even trailers for the New York Erotic Film Festival, and X-rated animated feature The Down and Dirty Duck, are funny in their own ways.