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.

What does the Holocaust have to do with us, anyway? In part two, Roderick Miller, the chair of the nonprofit organization Tracing the Past, gives a talk at TEDxVienna about the Holocaust and contemporary Europeans' perception of the space they live in.

What does the Holocaust have to do with us, anyway? In part three, Roderick Miller, the chair of the nonprofit organization Tracing the Past, gives a talk at TEDxVienna about the Holocaust and contemporary Europeans' perception of the space they live in.

Natalie Fee talks with candor and sensitivity about some usually taboo aspects of daily life and how they affect plastic pollution. She then shows a film clip by artist Chris Jordan that is very difficult to watch, as it shows how litter is killing seabirds.

Natalie Fee talks about impact the clip (at the end of the previous segment) had on her life and how she started out on her journey. One stop on that journey was a music video.

Natalie provides some facts and figures about how much garbage is getting flushed down the toilet in the UK, and goes on to tell us about a successful campaign she spearheaded, aimed at manufacturers of cotton swabs.

Natalie provides some tips for wasting less plastic and leaves us with a slogan to help us rethink our flushing habits. She involves the audience to bring the message home.

Natalie Fee concludes her Ted Talk with a few suggestions for what we can do to reduce how much single-use plastic we are sending into the earth's waterways.

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.

Romantic chemistry is all about warm, gooey feelings that gush from the deepest depths of the heart... right? Not quite. Actually, the real boss behind attraction is your brain, which runs through a very quick, very complex series of calculations when assessing a potential partner. Dawn Maslar explores how our five senses contribute to this mating game, citing some pretty wild studies along the way.