Brian's speech about William Randolph Hearst spearheading the charge against marijuana is accurate. Hearst controlled a vast media empire which allowed him to influence public opinion on such matters, leading to the government banning recreational use of marijuana in 1937.
The episode aired the day before 4/20.
The musical number "A Bag of Weed" is based on the song "Me Ol' Bamboo" from Chitty Chitty Bang Bang (1968).
The cutaway gag about Baby Mama (2008) says Tina Fey is 40 and Amy Poehler is 41. At the time this episode aired, Fey was 39 and Poehler was 38.