Leonard finally tells Penny how Sheldon saved his life and broke the elevator at the same time.

As the story goes, the theater of the Montreux Casino caught fire during a Frank Zappa concert in 1971. Members of the British band Deep Purple were in attendance and later wrote this song about the event. "Smoke on the Water" is one of the most famous songs in rock and roll history, known for its memorable guitar riff. Enjoy commentary from keyboardist Jon Lord after the concert footage!

The President and First Lady kick off an evening of poetry, music, and the spoken word at the White House.

Sigrid begins her tale of how she ended up in Italy, where she's now living. She was born in Minneapolis and raised in New York. As a young adult, she relocated to Switzerland in order to study early music. In this video, she talks about traveling to Europe for the first time and learning about the different genres of music prior to the classical era.

Canadian sensation Shawn Mendes made his debut at age 16 with the album "Handwritten." Here he performs the hit single "Stitches" in a duet with US singer and actress Hailee Steinfeld.

Here is Australian rock band INXS's single "Freedom Deep" from their 1993 album Full Moon, Dirty Hearts. Enjoy!

Lifestyle video blogger Aspyn Ovard demonstrates how she packed her suitcase efficiently for a recent trip to the Bahamas.

Taylor Swift's incredible performance of her track "I Knew You Were Trouble" at Capital FM's Jingle Bell Ball!

The First Lady welcomes the first act in an evening of poetry, music and spoken word at the White House. Pianist ELEW and bassist/singer Esperanza Spalding kick off the evening with an instrumental jazz fusion performance. Enjoy!

When Penny returns from visiting her family in Nebraska, Leonard is happy to see her. Sheldon, however, is much less welcoming when he learns that her family has the flu.

This video takes a look at hydrothermal vents and the novel life forms that thrive there in the absence of sunlight, fueled by underwater volcanoes. One of these harsh environments is the Axial Seamount off the West Coast of the United States.

"Sunday Bloody Sunday" is a song by the Irish rock band U2 that was written as a response to events related to conflict in Northern Ireland at the time. It is considered one of their signature songs, and is one of the band's most performed tracks.

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.

Justin Bieber headlined the 2015 Jingle Bell Ball in London, finishing his set with the song "Sorry."

Katie performs "I Will Be There" - the first single from her new album Ketevan.