My freshman year of college we had this on tape and watched it endlessly. We had a Gymkata movie poster and at the end of the year my roommate had everyone on our floor of the dorm sign it. Good times.
Others...
Plan 9 From Outer Space. This often gets mentioned as the worst film of all time, which is funny, because I've seen everything Ed Wood did and this is the best by a wide, wide margin. Everything about it is fabulous.
Orgy of the Dead. This was written by Ed Wood, but he didn't direct it. Basically, Criswell is sitting in a graveyard and recently deceased women dance and strip for him, one by one. That's the movie. One naked dancer gets whipped and Criswell shouts "Torture her, torture her. It PLEASURES me!" This was from Ed Wood's later days when he was a broken down drunk writing porn.
The Room. Just a wonderfully earnest piece of ship. A tour de force from a guy with a lot of money but no talent or understanding of how filmmaking works.
The Crawling Hand. An astronaut is blown up in space, and then a severed arm starts creeping around and strangling people. It's a little short on logic.
Tentacles. It's an incredibly bad Italian knock-off of Jaws, but with a giant octopus terrifying San Diego. The best scene is when a marine biologist giving a pep talk to some killer whales, encouraging them to go kill the octopus. The cast is unbelievable: Henry Fonda, John Huston, and Shelly Winters.
