Eating a Sandwich is the metaphor Future Ted uses for smoking cannabis, when telling his kids stories about them. This element is seen most commonly through flashbacks to Ted, Marshall, and Lily partaking in this activity in their college years together at Wesleyan University. It first appears in How I Met Everyone Else and is featured as a running gag throughout the series.
- How Lily Stole Christmas - Ted tells Marshal about a Christmas gift (an easy bake oven) that Lily had told Ted about in their college days after eating a sandwich. This episode happens before the "sandwich" metaphor is established.
- We're Not From Here - Robin eats a muffin not knowing that it contains marijuana.
- How I Met Everyone Else - Ted meets Marshall for the first time and sees him "eating a sandwich" in his dorm room, and the latter mistakes him for the dean. Ted is later seen eating a sandwich as well, and Marshall realizes he isn't really the dean. Also, later in the episode, in a flashforward to their class reunion in the year 2020, Ted, Marshall and Lily are seen sharing a large sandwich.
- The Fight - In a flashback to Ted's college years, Ted and Marshall are again seen eating a sandwich.
- Natural History - Another flashback to college Marshall eating a sandwich.
- Blitzgiving - Another college flashback to Ted and Marshall.
- A Change of Heart - The gang eats the sandwiches that Scooby brought.
- Tick Tick Tick - Ted and Marshall share a sandwich at a Groova Palooza.
- Symphony of Illumination - Scott is eating a sandwich inside Marshall's house.
- The Broath - Martin can be seen holding a sandwich.
- The Magician's Code - Part Two - A flashback to Marshall stapling himself in college while Ted is in the background eating a sandwich.
- The Stamp Tramp - Ted's videos show two college students eating sandwiches in his and Marshall's dorm room.
- The Ashtray - Becky and Ted shared a sandwich the night Ted met The Captain.
- Mom and Dad - Robin's cousin Claude introduces Ted to an elderly Rastafarian who is shown eating a sandwich.