HOA has a lot of pop culture references. These are the ones I've found. Post any others you find.

Harry Potter
Nina: Welcome to Hogwarts
Nina: I feel like I'm Harry Potter
Nina's mom: How's Harry Potter land?
Jerome: I've been at boarding school since I was 5
Mara: Wow! Even Harry Potter didn't go till he was 11!

Twilight
Fabian: Amber! This isn't Twilight!
Nina has a Taylor Lautner poster in her room

Star Wars
Alfie has a stormtrooper mask in his room

Doctor Who
Alfie has a toy Dalek in his room