MIXED MEDIA : A VIDEO SPECIAL : <i> Rated on a scale of one star (poor) to five (a classic).</i> : “VIVA LAS VEGAS” : Elvis Presley, Ann-Margret <i> MGM/UA laser disc ($34.99)</i> ** 1/2 : “WHERE THE BOYS ARE” : Dolores Hart, George Hamilton <i> MGM/UA laser disc ($34.99)</i> ** 1/2

Film festivals devoted to the attitudes of young America during the ‘60s invariably center on movies depicting social activism and alienation--such essential works as “Easy Rider” and “Woodstock.”

But there should also be a place reserved for films like these (both have just been re-released in deluxe, letter-box formats) from the first half of the decade--documents of the transitional years between the teen-age awakening of the late ‘50s and the full-scale revolution of the late ‘60s. It was a time in Hollywood when the main issue was how far you should go on the first date. In 1964’s “Viva Las Vegas,” the lure was two of America’s hottest young sex symbols: Elvis and Ann-Margret (whose rise to fame, ironically, was in “Bye-Bye Birdie,” a film that spoofed Presleymania). The dance routines and the love scenes--tucked around a hapless story about a race car driver and a swim instructor--may have scorched the screen at the time, but they are so tame by today’s standards that it’s hard to believe America was on the edge of a sexual explosion. The music, however, does sometimes connect.

“Where the Boys Are,” from 1960, might sound like just another empty-headed beach movie. But there is a thread of dramatic tension as four co-eds wrestle with questions of sex and the single girl during spring break in Ft. Lauderdale, Fla. Despite an undercurrent of rebellion against adult attitudes, the point of view about sex is so conservative that the film could have been shown at PTA meetings without a murmur of protest. The music (aside from cast member Connie Francis’ Top 10 title song) is mostly just comic relief.