Released in 1968, the animated film "Yellow Submarine" was inspired by the music of the Beatles and featured them in person as well. The spirit of 1960s counterculture is well-represented in this trailer. Enjoy!

The mop-topped fab four from Liverpool conquered the world with catchy, feel-good hits like this song “I Feel Fine” from 1964. In the video, you can catch the Beatles' sense of humor, with George pretending to sing the wrong words and Ringo riding a bicycle instead of playing the drums.

The production of the song "Now and Then" took place over five decades and is the product of conversations and collaborations between the four Beatles that go on to this day. The long mythologized John Lennon demo was first worked on in February 1995 by Paul, George and Ringo as part of The Beatles Anthology project but it remained unfinished, partly because of the impossible technological challenges involved in working with the vocals John had recorded on tape in the 1970s.

Leonard daydreams about saving Penny and her falling for him.

While Sheldon struggles with his take-out order, Leonard bids on what he thinks is a miniature time machine.

The boys decide to go to Long Beach in order to keep lying to Penny.

Penny tries to patch things up between Leonard and Sheldon when they are having a fight, but ends up making things worse!

When Penny dislocates her shoulder, Sheldon brings her home from the hospital and tucks her into bed.

Howard takes a moment in the tub to fantasize that Katee Sackhoff from Battlestar Galactica is in the tub with him. As it turns out, she has some advice for him.

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

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.

Penny invents a quiz to find out whether Sheldon or Leonard is smarter, which only reveals that both of them are completely uninformed about popular culture with the exception of Star Trek.

In this short scene, a deeply star-struck Sheldon meets one of his heroes, the great actor James Earl Jones, whom Sheldon knows as the voice of Darth Vader in the Star Wars movies.

Californian hip hop collective the Black Eyed Peas scored a global success with this song that questions the values of the modern world and the society we live in, and deals with issues such as racism, terrorism, pollution, gang crime, war, and intolerance. When hatred grows, and people and nations oppose each other, there's one question we find ourselves asking.

You've likely heard this one before... the catchy song "Lovefool" is the most famous hit from Swedish band The Cardigans.