When the unexpected happened, it was sometimes best to stay in character and try to get a bigger laugh. In particular, Ashton Kutcher, who played Kelso on the show, was willing to endure some painful knocks if it made the audience happy.

On set, the decor had to be just right in reflecting the decade of the 1970s. Behind the scenes, detail was also important when props were in use. We meet the man who coordinated many of the stunts and gags, and then catch up with some of the big-name guest stars who graced the show over the years.

Over the years, the show was blessed with many guest star appearances. Hollywood favorites like Bruce Willis, Lindsey Lohan, and Brooke Shields had a lot of fun working on set with the vibrant, enthusiastic cast.

Wilmer’s dressing room was closest to the studio and it served as a comfortable place for the cast members to hang out in between scenes. For Wilmer, it holds memories from the eight years of the show’s run, with his photo board and walls signed by cast and visitors alike.

When the show began, Debra Jo didn’t like her character Kitty’s hair, but changing her look was never going to be simple, and had to be written into the plot. One small fire later, and Kitty got a different hairdo, along with her husband’s attention.

All good things must come to an end, and for the cast, this really is their final goodbye. In this video, you can see the read-through of the last script and final filming of their last episode together. There’s a genuine warmth between the actors, and some tears, but all are thankful for the good times, friendship, and camaraderie the show has given them through the years.

Over the course of human history, thousands of languages have developed from what was once a much smaller number. How did we end up with so many? And how do we keep track of them all? Alex Gendler explains how linguists group languages into language families, demonstrating how these linguistic trees give us crucial insights into the past.

"You're a fishmonger!" By taking a closer look at Shakespeare's words, and particularly his insults, we can see why he is known as a master playwright whose works appeal to audiences all over the world.

When we look at insults used in Shakespeare's play "Romeo and Juliet," we get a new insight into dynamics between the characters and how they relate to the development of the story.

In this scene from the Star Trek episode "The Enemy Within," a transporter malfunction creates an evil Kirk, who proceeds to come aboard the ship.

After the Enterprise crew catch a virus that removes their inhibitions, one crew member rambles angrily about how humans don't belong in space and threatens Sulu with a knife.

In the Star Trek episode "The Enemy Within," the Enterprise crew finally get rid of an evil version of Captain Kirk using the transporter.

Kirk tries to literally slap Spock into helping him save the ship, but Spock, infected with the virus, can only lament about spending a whole lifetime learning to hide his feelings. Suddenly, Kirk also seems to be acting strangely.

In these scenes from a 1967 episode of the classic American sci-fi series Star Trek, Captain Kirk is held prisoner and Spock mounts a daring rescue.

Captain Kirk finds himself in Olympus, and face to face with the Greek god, Apollo... or so it would seem! But what might a classical deity want from the stunned and bemused Star Trek crew?