The episodes "Something Old" and "Something New" mirror the final two episode titles of season 2 ("Something Borrowed" and "Something Blue").
During laser tag, there are two references to the 1994 movie, Léon: The Professional. When Barney is giving a pep talk to his team one of the boys asks him, "What does that have to do with laser tag?" To which Barney responds in his face, "Everything!" This is similar to Gary Oldman's line in The Professional where he responds to a fellow officer asking who he should get to which Oldman's character responds, "Everyone!" The second reference is when Barney is perched above a doorway to shoot some kids in the back and then swings down to get two more kids while hanging upside down. This is exactly like a scene in The Professional where Léon does the same exact thing to police officers trying to enter his apartment.
When Ted is at the door of the apartment he delivers the following line "Look, I came here to chew bubblegum and pack boxes...and I'm all out of bubblegum." This line is a reworded line from the movie "They Live" starring Rowdy Roddy Piper in which Piper's character states "I have come here to chew bubblegum and kick ass...and I'm all out of bubblegum."
"El Ganso con la Riñonera" actually means "the Goose with the Fanny Pack". In some Spanish speaking countries "goose" is a mild insult.
In the episode The Possimpible, it states on Lily's resume that she is fluent in Italian. In this episode, however, Lily claims that the move to Rome will be difficult because her and Marshall don't know the language.