In this episode Robin had food poisoning and Barney and Ted made fun of her saying she's pregnant because she vomited. In real life, the actress, Cobie Smulders who played Robin was actually pregnant at that time.
When Marshall presents his pie chart of his favorite bars, the bar that is in second place is called McGee's, the real life New York City bar McClaren's is based on.
Milt, the homeless guy, actually does the correct math on the amount of years it would take for Ted to give him a dollar a day for a million days. As it would be just over 2,739 years.
Marshall's Venn diagram with Cecilia at the intersection of the two circles is a reference to the lyrics of the Simon and Garfunkel song, "Cecilia". The opening lines of this song are, "Cecilia, you're breaking my heart / you're shaking my confidence daily..."
Lily does not appear in the epsiode, despite flashbacks, as Alyson Hannigan was on maternity leave.