Season 5, Episode 1: Definitions

Original Air Date—21 September 2009

As Ted begins his new career as a professor and is about to meet his future wife, Lily forces Barney and Robin to have "the talk" and define their new relationship.

Season 5, Episode 2: Double Date

Original Air Date—28 September 2009

Ted goes on a blind date with the same woman he went on a blind date with seven years ago, and Barney and Marshall find Lily's stripper look-alike.

Season 5, Episode 3: Robin 101

Original Air Date—5 October 2009

When Robin fears that Barney is cheating on her, she soon discovers that he is spending his evenings with Ted learning everything there is to know on how to date her

Season 5, Episode 4: The Sexless Innkeeper

Original Air Date—12 October 2009

When Lily and Marshall realize that Robin and Barney are the perfect double-date friends, they try too hard to impress and come on too strong. Meanwhile, Ted gets a new nickname from Barney after an unsuccessful hook-up.

Season 5, Episode 5: Duel Citizenship

Original Air Date—19 October 2009

Ever since Marshall and Lily got married, Ted feels that his "best bro" Marshall has turned from being a "me" to a "we". That's why Ted is so excited when Marshall agrees to recreate one of their crazy college road trips to Chicago's Gazola's pizza joint, which is closing. But this trip is not quite what Ted was expecting as Marshall invites Lily. As Lily's presence changes the nature of the road trip, Ted tries to regain what he wanted this trip to be. Meanwhile, Robin may be deported unless she becomes a US citizen. Robin, a patriotic Canadian, isn't sure if she wants to become an American. Barney, who doesn't understand why anyone wouldn't want to be American, helps Robin become his version of American. But when Robin's withdrawal symptoms become too much for her to handle, she falls off the wagon. This experience shows her where she really fits and where her patriotic heart lies.

Season 5, Episode 6: Bagpipes

Original Air Date—2 November 2009

Despite their best efforts to be the perfect couple, Barney's know-it-all attitude gets him in trouble with Robin and they are forced to ask Marshall and Lily for relationship advice.

Season 5, Episode 7: The Rough Patch

Original Air Date—9 November 2009

After Barney and Robin hit a rough patch in their relationship, Lily devises the perfect plan to break them up, calling in help from Robin's famous friend, Alan Thicke.

Season 5, Episode 8: The Playbook

Original Air Date—16 November 2009

When Barney hooks up with a woman Lily had been saving for Ted, she gets revenge by stealing his "playbook," which contains all the moves he uses to pick up women. But will Barney have the last laugh?

Season 5, Episode 9: Slapsgiving 2: Revenge of the Slap

Original Air Date—23 November 2009

Barney freaks out when Marshall bequeaths a "slap bet" slap to Ted and Robin. Meanwhile, Lily's estranged father shows up for Thanksgiving.

Season 5, Episode 10: The Window

Original Air Date—7 December 2009

Maggie a girl next door Ted has wanted to date for years has suddenly broken up with her latest boyfriend, giving him and many other guys a chance to score with her.

Season 5, Episode 11: Last Cigarette Ever

Original Air Date—14 December 2009

The gang struggles to quit smoking while Robin clashes with her new jaded co-worker.

Season 5, Episode 12: Girls Vs. Suits

Original Air Date—11 January 2010

Barney chooses between wearing suits and sleeping with a sexy bartender. Meanwhile, Ted gets ever closer to meeting "the mother".

Season 5, Episode 13: Jenkins

Original Air Date—18 January 2010

When Marshall finds out he's the "reacher" in his relationship with Lily and not the "settler," he considers pursuing a sexy and cool female coworker. Meanwhile, Ted finds out Robin is a drinking game for his architecture students.

Season 5, Episode 14: Perfect Week

Original Air Date—1 February 2010

When Barney is about to complete the perfect week - landing seven different girls in seven days - the gang roots him on in order to forget about their own miserable week.

Season 5, Episode 15: Rabbit or Duck

Original Air Date—8 February 2010

Barney runs into problems when he displays his cell phone number during the Super Bowl, Ted asks Marshall and Lily to arrange a marriage for him, and Robin thinks that her co-anchor has asked her out on a date.

Season 5, Episode 16: Hooked

Original Air Date—1 March 2010

When the gang tries to convince Ted that he is being strung along by Tiffany, they reflect about relationships where each of them has been in the same situation.

Season 5, Episode 17: Of Course

Original Air Date—8 March 2010

After the guys discover that Robin deliberately got Barney hooked up with an incompatible female writer, they find out that that they didn't realize that Robin hasn't been handling their breakup very well.

Season 5, Episode 18: Say Cheese

Original Air Date—22 March 2010

Ted angers Lily when he brings a random date to her birthday party, so she is forced to remind him of all the other random women he has brought along to important functions, only to discover that they weren't "the one."

Season 5, Episode 19: Zoo or False

Original Air Date—12 April 2010

Marshall comes up with a number of different outrageous and embarrassing stories to explain how he was mugged in Central Park, but which of his stories is the truth?

Season 5, Episode 20: Home Wreckers

Original Air Date—19 April 2010

Ted reacts to his mom's second wedding by making the capricious decision to buy his "dream house," while everyone tries to figure out whether Barney or Robin cried at the wedding.

Season 5, Episode 21: Twin Beds

Original Air Date—3 May 2010

As Robin contemplates moving in with her new boyfriend Don, Ted and Barney both decide that they want her back. Meanwhile, Marshall and Lily think they've revolutionized modern marriage when they begin sleeping in separate beds.

Season 5, Episode 22: Robots Vs. Wrestlers

Original Air Date—10 May 2010

Barney is worried that the old gang is falling apart when Ted blows off a "Wrestlers vs. Robots" competition so that he can stay at a snobby party.

Season 5, Episode 23: The Wedding Bride

Original Air Date—17 May 2010

Ted is livid when he discovers that the man Stella left Ted for at the altar wrote a blockbuster movie about the incident, and portrays Ted as the bumbling, mean-spirited bad guy.

Season 5, Episode 24: Doppelgangers

Original Air Date—24 May 2010

Marshall and Lily think they've spotted Barney's doppelganger, which means that they can start trying to have a baby, but it's really Barney in disguise. Meanwhile, Ted goes blonde and Robin considers taking an anchor job in Chicago.