Friends

Friends is one of the most iconic and beloved television shows of all time - and one of the most brilliant lines from the hit sitcom came courtesy of some great Jennifer Anniston improvisation. It was in the episode The One After Vegas, when Ross and Rachel woke up after a drunken evening in Sin City with no recollection of the fact that they had gotten married to each other the night before. When they were informed about it by the other Friends, Rachel responded with the line "This isn't a marriage, this is just the world's worst hangover!" which was superbly made up on the spot by Anniston.

House

Hugh Laurie is an outrageously talented actor, so it should come as no surprise that one of the funniest scenes in House - a medical drama in which he starred as the titular character Gregory House - was totally ad libbed by the Brit. In the opening season two episode Acceptance, Laurie's character was mad at James Wilson for having sided with Stacy Warner in a quarrel. In response to this, House said "Look, I know you're friends with her, but there's a code! Bros before hos, man!" It was so unlike anything you'd expect him to say that it was hilarious - and it was clear to see that Robert Sean Leonard who plays WIlson was cracking up about it!

Community

In the Introduction to Teaching episode of the great sitcom Community, one of the show's main characters - Abed Nadir, played by Danny Pudi - begins taking a class discussing popular Hollywood actor Nicolas Cage. When he gets up in front of the class to deliver a presentation about Cage, Pudi improvises a scene in which he suddenly starts acting like him - going totally crazy and speaking in an overly dramatic fashion, just like Cage often does in his movie roles. Everyone in the class looks totally stunned - and it's hardly surprising! They didn't expect to see Abed as Cage acting like a "sexy cat" that day!

The Simpsons

In The Simpsons episode You Only Move Twice, the brilliant Albert Brooks guest-starred as the eccentric owner of the Globex Corporation - and Homer's new employer - Hank Scorpio. Scorpio seemed to be the perfect boss (before being revealed to be an evil genius, that is) and encouraged Homer to implement his own ideas. One of those ideas was that his team were given hammocks, because working so hard was making them tired. When Homer went to Scorpio with the idea, he loved it and Brooks improvised a scene in which he said hammocks could be purchased at the nearby "Hammock District". Writer Josh Weinstein has since said that Dan Castellaneta's reactions as Homer were "exactly like someone talking to Albert Brooks".

Parks and Recreation

Given its incredibly talented comedy cast, you'd be forgiven for thinking that a lot of Parks and Recreation was ad libbed - but you would also be wrong. That being said, one of the funniest lines in the show's entire run was made up on the spot by none other than current Hollywood superstar Chris Pratt. In the episode Flu Season, Pratt's character, Andy Dwyer, typed his co-worker Leslie's sickness symptons into his computer to find out what was wrong with her. In a completely improvised moment, Pratt's character then stated that the computer had deduced that Leslie was suffering from "network connectivity issues", which is undeniably brilliant.

The Office

Ever since the original British version was airing, The Office had a reputation for having some of the most awkward scenes in television history - but none were more awkward than a hilarious improvised moment courtesy of Steve Carell in the U.S. adaptation of the show. It came in the episode Gay Witch Hunt, when Carell's character Michael Scott offended his employee Oscar Martinez by calling him "faggy" without realising Oscar was actually homosexual. As a result, Michael attempted to reconcile with him in front of his workforce by giving him a hug. The improvised moment came when Carell's character added a kiss to the scene, shocking Oscar Nunez - the actor who played Oscar Martinez. The look you see on Nunez's face when the kiss happens was a genuine reaction, and it's pretty damn funny.