January 2009

- Robin and Ted become friends with benefits to prevent arguments, they stop when Ted realizes that Barney is upset by it. [412 Benefits] ​

- Tues-Thurs. Lily's flight from Seattle is delayed for two days due to a big snowstorm, Ted & Barney run MacClarens. [413 Three Days of Snow]​

February 2009

 - After receiving notice Robin will be deported back to Canada if she doesn't find a job in 7 days Barney helps her get a job at Come On, Get Up New York! [414 The Possimpible]​

- The Goliath National Bank project is cancelled, though Ted doesn't find out till a month later. [418 Old King Clancy]​
March 2009

- Ted dates his college girlfriend Karen for a few weeks before they break up again. [416 Sorry Bro, 417 The Front Porch]​

- Ted discovers the Goliath National Bank project was cancelled a month ago but Barney and Marshall had been lying to him that it was still going. He ends up getting the job of designing a new room but is fired when he attempts to re-design it. [418 Old King Clancy]​

- Barney tells an offensive joke to Lily and she is not seen for four weeks. [420 Mosbius Designs. In reality this was because of Alyson Hannigan's pregnancy]​
April 2009

- Ted starts his own architecture firm, Mosbius Designs. It doesn't last long. [420 Mosbius Designs]​

- Ted attends the wedding of his high school friends in Cleveland, and cries during the toast. [701 The Best Man. Dating this is a bit tricky as Ted says he was fired "a week ago", which was in March, but he mentions Mosbius Designs, which he started a few weeks later.]

- Barney sleeps with his 200th woman, a female bodybuilder. [422 Right Place, Right Time]

- A chance encounter between Ted and Stella & Tony results in him being offered a teaching job. [422 Right Place, Right Time]

- Barney is arrested for having excessive speeding tickets, after trying to prove he can talk his way out of a speeding ticket and repeatedly failing. [423 As Fast As She Can]

- 22nd. The beginning of The Leap. For the next three days after this Ted works on his design for Rib Town. [424 The Leap]​

- 25th. Teds 31st birthday party, he's attacked by a goat and hospitalized. [It's already been established Teds birthday is on April 25th. 424 The Leap]​

- 26th. Robin & Barney get together, over the summer they continue to secretly hook up, Ted does a presentation for Rib Town. They turn him down for a design from Sven. [424 The Leap]​

May 2009

- 8th. Ted walks into the apartment to find a goat [According to 409 The Naked Man. This is inconsistent as the goat was first in the apartment just before Teds birthday which has already been established as being on April 25th in Season 3 so either Ted had his party really late this year and the above dates are wrong, the goat was still in the apartment at this time or the writers just messed up!]​

June 2009

- Lily finds out out that Robin and Barney kissed and is ecstatic at the idea she'll have someone to double date with. She's crushed when they tell her they've decided it was a one off thing. [501 Definitions]​

July 2009

- Ted attends the wedding of his high school friends, Alex and Jessica, and cries during the toast. His friend Punchy records the video and turns makes a remix in it, which goes viral and is especially popular in Finland. [Classic Schmosby!] [Three months after the previous wedding Ted attended. 701 The Best Man]

Summer 2009

- Ted decides to take a job as a college professor. [424 The Leap. He decides sometime between his birthday, at the end of April, and when he starts the job in September]

- Barney goes water skiing, while wearing a suit. [Photo shown in 512 Girls vs. Suits]

- Trilogy Time 2009. Ted and Marshall go to Barneys apartment to watch the Star Wars trilogy. totally unaware about the fact that Barney and Robin are hooking up. [720 Trilogy Time]​

September 2009​

- Ted starts his job as a college professor. He accidentally goes into the wrong classroom on his first day and is unaware his future wife, Tracy, is in that same room ​[501 Definitions]​. Tracy starts attending college in order to pursue her dream of fighting poverty. She meets Cindy and offers her a room at her apartment, which she accepts. [916 How Your Mother Met Me]

- After secretly hooking up all summer Barney and Robin officially become a couple. [501 Definitions]​

- Ted goes on a blind date with Jen for the second time since 2002. [502 Double Date]​

- The gang finds the third doppleganger, Stripper Lily. [502 Double Date]​

October 2009

- The gang buys their bottle of $2500 scotch, as planned a year earlier. They're disappointed to find it tastes much like regular, much cheaper scotch. [a year after 404 Intervention]​

- Barney takes a class on dating Robin, which is taught by Ted. [503 Robin 101]​

- Gazola's Pizza in Chicago closes, prompting one last trip there by Ted, Marshall and Lily. [505 Dual Citizenship]​

- Robin becomes a dual citizen of both the USA and Canada. [505 Dual Citizenship]​

November 2009

- Robin and Barney break up. [507 The Rough Patch]​

- Don starts as co-anchor with Robin at Come On, Get Up New York! [508 The Playbook]​

- 26th. Thanksgiving at Marshall & Lily's, Lily reconciles with her dad, The fourth slap is given. [509 Slapsgiving 2]​

December 2009

- Maggie Wilks, Ted's ultimate girl next door, breaks up with her boyfriend, and as agreed 4 years earlier her neighbour lets Ted know she's single. Ted rushes to see her but ultimately she finds meets up childhood sweetheart and they later get married, closing the window forever. [510 The Window]

- 8th. 8.29pm. Marshall makes a list for himself to read when he's sixty years old saying that he hopes he's still married to Lily, and if possible to let him know if time travel exists. Little does he know future Marshall is in the bar too and arranges for present Marshall and Lily to get some free chicken wings [Exact date in time is mentioned in 510 The Window]

- 31st. Robin makes a new years resolution to get a job at Worldwide News. Later on that night she decides to drink an entire bottle of scotch. [612 False Positive]​
Sometime in 2009

- Ted's future girlfriend, Zoe Pierson, sets a car on fire after a Guns 'N Roses concert and is arrested. [Date given in 605 Architect of Destruction]