S04E21: The Three Days Rule
Ted breaks one of Barney and Marshall's relationship rules, texting a woman he recently met, so the pair play a joke on Ted by pretending to be the woman.
Previous Episode 
Season 1
Pilot
S1E1 / 19 Sep 2005
Purple Giraffe
S1E2 / 26 Sep 2005
Sweet Taste of Liberty
S1E3 / 03 Oct 2005
Return of the Shirt
S1E4 / 10 Oct 2005
Okay Awesome
S1E5 / 17 Oct 2005
The Slutty Pumpkin
S1E6 / 24 Oct 2005
Matchmaker
S1E7 / 07 Nov 2005
The Duel
S1E8 / 14 Nov 2005
Belly Full of Turkey
S1E9 / 21 Nov 2005
The Pineapple Incident
S1E10 / 28 Nov 2005
The Limo
S1E11 / 19 Dec 2005
The Wedding
S1E12 / 09 Jan 2006
Drumroll, Please
S1E13 / 23 Jan 2006
Zip, Zip, Zip
S1E14 / 06 Feb 2006
Game Night
S1E15 / 27 Feb 2006
Cupcake
S1E16 / 06 Mar 2006
Life Among the Gorillas
S1E17 / 20 Mar 2006
Nothing Good Happens After 2 A.M.
S1E18 / 10 Apr 2006
Mary the Paralegal
S1E19 / 24 Apr 2006
Best Prom Ever
S1E20 / 01 May 2006
Milk
S1E21 / 08 May 2006
Come On
S1E22 / 15 May 2006
Season 2
Where Were We?
S2E1 / 18 Sep 2006
The Scorpion and the Toad
S2E2 / 25 Sep 2006
Brunch
S2E3 / 02 Oct 2006
Ted Mosby, Architect
S2E4 / 09 Oct 2006
World's Greatest Couple
S2E5 / 16 Oct 2006
Aldrin Justice
S2E6 / 23 Oct 2006
Swarley
S2E7 / 06 Nov 2006
Atlantic City
S2E8 / 13 Nov 2006
Slap Bet
S2E9 / 20 Nov 2006
Single Stamina
S2E10 / 27 Nov 2006
How Lily Stole Christmas
S2E11 / 11 Dec 2006
First Time in New York
S2E12 / 08 Jan 2007
Columns
S2E13 / 22 Jan 2007
Monday Night Football
S2E14 / 05 Feb 2007
Lucky Penny
S2E15 / 12 Feb 2007
Stuff
S2E16 / 19 Feb 2007
Arrivederci, Fiero
S2E17 / 26 Feb 2007
Moving Day
S2E18 / 19 Mar 2007
Bachelor Party
S2E19 / 09 Apr 2007
Showdown
S2E20 / 30 Apr 2007
Something Borrowed
S2E21 / 07 May 2007
Something Blue
S2E22 / 14 May 2007
Season 3
Wait for It
S3E1 / 24 Sep 2007
We're Not from Here
S3E2 / 01 Oct 2007
Third Wheel
S3E3 / 08 Oct 2007
Little Boys
S3E4 / 15 Oct 2007
How I Met Everyone Else
S3E5 / 22 Oct 2007
I'm Not That Guy
S3E6 / 29 Oct 2007
Dowisetrepla
S3E7 / 05 Nov 2007
Spoiler Alert
S3E8 / 12 Nov 2007
Slapsgiving
S3E9 / 19 Nov 2007
The Yips
S3E10 / 26 Nov 2007
The Platinum Rule
S3E11 / 10 Dec 2007
No Tomorrow
S3E12 / 17 Mar 2008
Ten Sessions
S3E13 / 24 Mar 2008
The Bracket
S3E14 / 31 Mar 2008
The Chain of Screaming
S3E15 / 14 Apr 2008
Sandcastles in the Sand
S3E16 / 21 Apr 2008
The Goat
S3E17 / 28 Apr 2008
Rebound Bro
S3E18 / 05 May 2008
Everything Must Go
S3E19 / 12 May 2008
Miracles
S3E20 / 19 May 2008
Season 4
Do I Know You?
S4E1 / 22 Sep 2008
The Best Burger in New York
S4E2 / 29 Sep 2008
I Heart NJ
S4E3 / 06 Oct 2008
Intervention
S4E4 / 13 Oct 2008
Shelter Island
S4E5 / 20 Oct 2008
Happily Ever After
S4E6 / 03 Nov 2008
Not a Father's Day
S4E7 / 10 Nov 2008
Woooo!
S4E8 / 17 Nov 2008
The Naked Man
S4E9 / 24 Nov 2008
The Fight
S4E10 / 08 Dec 2008
Little Minnesota
S4E11 / 15 Dec 2008
Benefits
S4E12 / 12 Jan 2009
Three Days of Snow
S4E13 / 19 Jan 2009
The Possimpible
S4E14 / 02 Feb 2009
The Stinsons
S4E15 / 02 Mar 2009
Sorry, Bro
S4E16 / 09 Mar 2009
The Front Porch
S4E17 / 16 Mar 2009
Old King Clancy
S4E18 / 23 Mar 2009
Murtaugh
S4E19 / 30 Mar 2009
Mosbius Designs
S4E20 / 13 Apr 2009
The Three Days Rule
S4E21 / 27 Apr 2009
Right Place, Right Time
S4E22 / 04 May 2009
As Fast as She Can
S4E23 / 11 May 2009
The Leap
S4E24 / 18 May 2009
Season 5
Definitions
S5E1 / 21 Sep 2009
Double Date
S5E2 / 28 Sep 2009
Robin 101
S5E3 / 05 Oct 2009
The Sexless Innkeeper
S5E4 / 12 Oct 2009
Duel Citizenship
S5E5 / 19 Oct 2009
Bagpipes
S5E6 / 02 Nov 2009
The Rough Patch
S5E7 / 09 Nov 2009
The Playbook
S5E8 / 16 Nov 2009
Slapsgiving 2: Revenge of the Slap
S5E9 / 23 Nov 2009
The Window
S5E10 / 07 Dec 2009
Last Cigarette Ever
S5E11 / 14 Dec 2009
Girls vs. Suits
S5E12 / 11 Jan 2010
Jenkins
S5E13 / 18 Jan 2010
Perfect Week
S5E14 / 01 Feb 2010
Rabbit or Duck
S5E15 / 08 Feb 2010
Hooked
S5E16 / 01 Mar 2010
Of Course
S5E17 / 08 Mar 2010
Say Cheese
S5E18 / 22 Mar 2010
Zoo or False
S5E19 / 12 Apr 2010
Home Wreckers
S5E20 / 19 Apr 2010
Twin Beds
S5E21 / 03 May 2010
Robots vs. Wrestlers
S5E22 / 10 May 2010
The Wedding Bride
S5E23 / 17 May 2010
Doppelgangers
S5E24 / 24 May 2010
Season 6
Big Days
S6E1 / 20 Sep 2010
Cleaning House
S6E2 / 27 Sep 2010
Unfinished
S6E3 / 04 Oct 2010
Subway Wars
S6E4 / 11 Oct 2010
Architect of Destruction
S6E5 / 18 Oct 2010
Baby Talk
S6E6 / 25 Oct 2010
Canning Randy
S6E7 / 01 Nov 2010
Natural History
S6E8 / 08 Nov 2010
Glitter
S6E9 / 15 Nov 2010
Blitzgiving
S6E10 / 22 Nov 2010
The Mermaid Theory
S6E11 / 06 Dec 2010
False Positive
S6E12 / 13 Dec 2010
Bad News
S6E13 / 03 Jan 2011
Last Words
S6E14 / 17 Jan 2011
Oh Honey
S6E15 / 07 Feb 2011
Desperation Day
S6E16 / 14 Feb 2011
Garbage Island
S6E17 / 21 Feb 2011
A Change of Heart
S6E18 / 28 Feb 2011
Legendaddy
S6E19 / 21 Mar 2011
The Exploding Meatball Sub
S6E20 / 11 Apr 2011
Hopeless
S6E21 / 18 Apr 2011
The Perfect Cocktail
S6E22 / 02 May 2011
Landmarks
S6E23 / 09 May 2011
Challenge Accepted
S6E24 / 16 May 2011
Season 7
The Best Man
S7E1 / 19 Sep 2011
The Naked Truth
S7E2 / 19 Sep 2011
Ducky Tie
S7E3 / 26 Sep 2011
The Stinson Missile Crisis
S7E4 / 03 Oct 2011
Field Trip
S7E5 / 10 Oct 2011
Mystery vs. History
S7E6 / 17 Oct 2011
Noretta
S7E7 / 24 Oct 2011
The Slutty Pumpkin Returns
S7E8 / 31 Oct 2011
Disaster Averted
S7E9 / 07 Nov 2011
Tick Tick Tick
S7E10 / 14 Nov 2011
The Rebound Girl
S7E11 / 21 Nov 2011
Symphony of Illumination
S7E12 / 05 Dec 2011
Tailgate
S7E13 / 02 Jan 2012
46 Minutes
S7E14 / 16 Jan 2012
The Burning Beekeeper
S7E15 / 06 Feb 2012
The Drunk Train
S7E16 / 13 Feb 2012
No Pressure
S7E17 / 20 Feb 2012
Karma
S7E18 / 27 Feb 2012
The Broath
S7E19 / 19 Mar 2012
Trilogy Time
S7E20 / 09 Apr 2012
Now We're Even
S7E21 / 16 Apr 2012
Good Crazy
S7E22 / 30 Apr 2012
The Magician's Code (1)
S7E23 / 14 May 2012
The Magician's Code (2)
S7E24 / 14 May 2012
Season 8
Farhampton
S8E1 / 24 Sep 2012
The Pre-Nup
S8E2 / 01 Oct 2012
Nannies
S8E3 / 08 Oct 2012
Who Wants to Be a Godparent?
S8E4 / 15 Oct 2012
The Autumn of Break-Ups
S8E5 / 05 Nov 2012
Splitsville
S8E6 / 12 Nov 2012
The Stamp Tramp
S8E7 / 19 Nov 2012
Twelve Horny Women
S8E8 / 26 Nov 2012
Lobster Crawl
S8E9 / 03 Dec 2012
The Over-Correction
S8E10 / 10 Dec 2012
The Final Page (1)
S8E11 / 17 Dec 2012
The Final Page (2)
S8E12 / 17 Dec 2012
Band or DJ?
S8E13 / 14 Jan 2013
Ring Up!
S8E14 / 21 Jan 2013
P.S. I Love You
S8E15 / 04 Feb 2013
Bad Crazy
S8E16 / 11 Feb 2013
The Ashtray
S8E17 / 18 Feb 2013
Weekend at Barney's
S8E18 / 25 Feb 2013
The Fortress
S8E19 / 18 Mar 2013
The Time Travelers
S8E20 / 25 Mar 2013
Romeward Bound
S8E21 / 15 Apr 2013
The Bro Mitzvah
S8E22 / 29 Apr 2013
Something Old
S8E23 / 06 May 2013
Something New
S8E24 / 13 May 2013
Season 9
The Locket
S9E1 / 23 Sep 2013
Coming Back
S9E2 / 23 Sep 2013
Last Time in New York
S9E3 / 30 Sep 2013
The Broken Code
S9E4 / 07 Oct 2013
The Poker Game
S9E5 / 14 Oct 2013
Knight Vision
S9E6 / 21 Oct 2013
No Questions Asked
S9E7 / 28 Oct 2013
The Lighthouse
S9E8 / 04 Nov 2013
Platonish
S9E9 / 11 Nov 2013
Mom and Dad
S9E10 / 18 Nov 2013
Bedtime Stories
S9E11 / 25 Nov 2013
The Rehearsal Dinner
S9E12 / 02 Dec 2013
Bass Player Wanted
S9E13 / 16 Dec 2013
Slapsgiving 3: Slappointment in Slapmarra
S9E14 / 13 Jan 2014
Unpause
S9E15 / 20 Jan 2014
How Your Mother Met Me
S9E16 / 27 Jan 2014
Sunrise
S9E17 / 03 Feb 2014
Rally
S9E18 / 24 Feb 2014
Vesuvius
S9E19 / 03 Mar 2014
Daisy
S9E20 / 10 Mar 2014
Gary Blauman
S9E21 / 17 Mar 2014
The End of the Aisle
S9E22 / 24 Mar 2014
Last Forever (1)
S9E23 / 31 Mar 2014
Last Forever (2)
S9E24 / 31 Mar 2014
Josh Radnor
Ted Mosby
Neil Patrick Harris
Barney Stinson
Jason Segel
Marshall Eriksen
Alyson Hannigan
Lily Aldrin
Cobie Smulders
Robin Scherbatsky
