Star Trek: The Original Series (TOS)

Star Trek originally aired on NBC, from September 8th 1966 through June 3rd 1969, for a total of 79 episodes in just over 3 years. You can download individual episodes from iTunes, with or without the "enhanced" starships and effects:

Example Storyline:
Episode 46, Season 2 (01/05/1968)

The Gamesters of Triskelion

Stardate 3211.7. On a mission to Gamma 2, Chekov, Jim, and Uhura experience a transporter malfunction and find themselves on a strange world. Scotty has no idea what happened to them. Spock scans the planet surface but can't find any trace of them.

Jim's team, meanwhile, is attacked by four strange humanoids. The crew is overpowered and fitted with "Collars of Obedience" by Galt, master Thrall of the planet Triskelion, and taken to prison cells.

The prisoners each have a Thrall "trainer" to help condition them for the wargames that are played constantly on Triskelion. Kirk's trainer is, predictably, a beautiful yet easily manipulated alien woman. She falls in love with him, and so Kirk naturally uses this to his advantage and proceeds to hit her in the face with his fist and knock her out.

Kirk steals his woman's cell key and frees himself and his crew. Galt sees this happening and suddenly appears, using the shock collars to regain control of the prisoners. He forces Jim into a fight against his minions, but Jim defeats them all. Galt has no choice but to promote all crew members, under the direction of The Providers (off-camera booming voices, sounding like the voice of God).

So Jim and crew eventually unveil the true nature of The Providers and Jim makes a bet with them: "Let me fight your best warriors and if I lose, you can have my whole crew, a fresh new set of warriors to play your games. But if I win," he continues, "you have to let us all go."

I won't spoil the ending.