The Adventure Game

Opening narration:
[FIRST SEASON] Many light years away, on the far side of the galaxy, in a region often visited by time-travelers, lies Arg. A small planet of little consequence. Naturally, the inhabitants of Arg get a bit fed up with trippers and tend to discourage them. Often they will even nick the essential crystal off their time machines and hide it. Visitors from planet Earth enquiring after their crystal can nevertheless feel quite at home here, because the Argons are a polite race and careful to adapt their shape so as not to frighten strangers. Unfortunately, they also have a regrettable sense of humor...

Opening narration:
[FOURTH SEASON] Many light years away, on the far side of the galaxy, in a region often visited by time-travelers, lies Arg. A small planet of little consequence. The Argons, a polite race, nevertheless have a regrettable sense of humor, and enjoy testing the wit and perspicacity of any visitors. This testing of alien intelligences has become rather a popular past-time for the Argons, and it's one of their top-rated television shows. Now, thanks to the miracle of hyperspace laser-relays, we can link up with Arg-o-Vision as another party of Earth visitors is about to set foot on the planet and encounter its problems for the very first time...