1. In Unbreakable Kimmy Schmidt, Lillian is seen drinking a can of Old Spanish, which 30 Rock fans will know is a made-up drink from the show.
2. And Mad Men gave a little nod to 30 Rock when Ted ordered an Old Spanish at a bar!
3. In the second season of Parks and Recreation, the MRI technician Leslie dates tells her she has the perfect uterus for triplets. Lo and behold, four seasons later, Leslie finds herself pregnant with triplets.
4. The Good Place references The Office many times, but you may not have noticed that Neil's mug reads "Existence's Best Boss."
5. You can also spot Parks and Recs star Li'l Sebastian living it up in lil horsey heaven in the background of The Good Place.
6. In Ben’s episode of Never Have I Ever, which was narrated by Andy Samberg, a poster of the actor can be seen on Ben's bedroom wall.
8. Another world's crossover here – in the trial episode of Kimmy Schmidt, Kimmy says that the Reverend convinced the women he kidnapped that he came up with the "buy the world a Coke" advert. The Reverend is played by Jon Hamm, whose Mad Men character appears to come up with that same commercial while on a retreat.
9. In the third season of Buffy the Vampire Slayer, Faith visits Buffy in a dream, and says the cryptic line: "Little Miss Muffet counting down from 7-3-0." This foreshadows both the introduction of Dawn, and Buffy's death two years later.
10. When Lacie is scrolling through social media in the Black Mirror episode "Nosedive," a post from Michael Callow appears on-screen, which reads: "just got thrown out of the zoo again." This is a nod to the first-ever episode of the show, where Prime Minister Michael Callow assaults a pig.
11. In Community, someone dressed as Beetlejuice appears in the background, after the character is mentioned three times!
12. When he's cooking meth in the first episode of Breaking Bad, Walt's trousers fly off. In the fifth and final season of the show, those same trousers – looking much worse for wear – make a cameo.
13. In the first episode of the second season of Broad City, there are two girls riding the subway dressed exactly like Abbi and Ilana were on the day they got maced in season one.
14. And while you may have noticed the episode "Burning Bridges" was a homage to Mrs Doubtfire, you may not have spotted Mara Wilson, who was in the original movie, as the waitress.
15. Every Friend's fan knows that Monica has 11 towel categories, but you may not have noticed the neatly labelled boxed up towels when the girls are moving apartments.
16. And finally, the doodleboard in Joey's apartment often summarises the major plot of that particular episode!
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