John and Will must battle it out with a couple of aliens, played by Michael Ansara and Kurt Russell.
A few years ago Kurt Russell was shown footage of himself in The Challenge on a US talk show. Russell had to hold back laughter and made fun of his own "bad acting". Today, when I watch this episode I remember that interview.
At one point in The Challenge Ansara makes a very sexist comment about women's duties on earth to which Don responds "I can see the boys at the club (on his planet) laughing about it now". Funny stuff.
The Challenge was more fun when I was a child of the 1970s but it still has the odd moment I can enjoy as an adult. I read somewhere that Ansara was originally offered the role of the hunter alien in season three's - Hunter's Moon - but the role went to cheaper to pay actor, Vincent Beck.