There are bad movies, and there are really bad movies.

The first type of bad movie is one you never want to see again, like "The Postman" or "Waterworld" or anything else starring Kevin Costner.

The second type, however, is so bad that you never tire of marveling at its awfulness. From the incompetent direction to the improbable story to the inexcusable acting, a truly great bad movie stands the test of time. You know, like "Showgirls." And thanks to DVD, these cinematic atrocities can be enjoyed again and again.

They don't get much worse than 1981's "Tarzan, the Ape Man," coming to DVD on June 8. This is the film where Tarzan is second banana to Jane, this time played by "10" star Bo Derek and directed by her husband, the late John Derek.

How poor Richard Harris got talked into playing Jane's father I'll never know, but I suspect he was drunk at the time. The plot, such as it is, has Jane and her father exploring Darkest Africa, where they run afoul of hostile natives and other unsavory characters. But all of this is just an excuse for Bo to take off her clothes, which she does early and often.

Eventually, Tarzan shows up in the form of Miles O'Keeffe. Mind you, O'Keeffe doesn't have any lines, but that is just as well because O'Keeffe has the screen presence of a filleted tuna.

The DVD, to be released by Warner Home Video, will include the widescreen version of the film and retail for $19.97.

Tarzan isn't the only pulp literary hero to receive Hollywood's schlock treatment. For another example, look no further than the 1985 sword-and-sorcery disaster "Red Sonja," based loosely on a character created by Robert E. Howard, who also created Conan.

In fact, Conan appears in "Red Sonja." Sort of. Arnold Schwarzenegger, who stars in 1981's "Conan the Barbarian," fills a similar role here. He also gets top billing over Brigitte Nielsen, the former Mrs. Sylvester Stallone who plays the title role.

The statuesque Nielsen looks the part of an Amazon warrior, but she doesn't act it. She wouldn't last five minutes against Xena. For his part, Schwarzenegger looks like he just wants a quick paycheck.

Sandahl Bergman, Schwarzenegger's love interest in "Conan," co-stars as the evil queen who slaughters Sonja's family. As a result, "Red Sonja" spends a lot of time reminding you of a better movie with the same actors.

Warner Home Video's widescreen DVD, due on July 6, will retail for $14.97.

Finally, on Sept. 7 you will believe a man can slither. Dirk Benedict stars in the 1973 bad-movie classic with the funny name "Sssssss."

Years before starring in "Battlestar Galactica" and "The A-Team," Benedict plays an unlucky college student whose professor decides to turn him into a giant-size cobra.

Universal's DVD will feature an anamorphic widescreen print of the film. Other features and the price will be announced later, but expect this to be another bare bones, bargain-priced release.

The best thing about "Sssssss" is its title. When "Sssssss" airs on television, you get to hear some unlucky announcer say, "Coming up next, 'Sssssss' " and "We now return to 'Sssssss.' "

Believe me, listening to a baritone-voiced announcer say, "Sssssss," over and over is pretty funny under the right circumstances, which usually involve a keg or Dad's liquor cabinet.

Of course, if you're watching "Sssssss" on DVD, there is no announcer. You have to say "Sssssss" yourself and pretend. It will probably help to have that keg. But even without it, "Sssssss" is more fun than watching Kevin Costner deliver the mail.