South Park: Stick of Truth is absolutely amazing.

I stole this from the user SqueakyG on GameFAQs, but they list all of the episodes that are heavily referenced:

s01e01 - Cartman Gets an Anal Probe - How it all began s01e11 - Tom's Rhinoplasty - Mr Garrison gets The Hoff s02e17 - Gnomes - Underpants Gnomes s03e11 - Chinpokomon - I got Shoe! s04e17 - A Very Crappy Christmas - Mr Hankey and family s06e06 - Professor Chaos - Birth of an alterego s06e11 - Child Abduction is Not Funny - How the Mongorians came to South Park s06e14 - The Death Camp of Tolerance - Lemmiwinks' magical journey through Mr Slave's ass s07e14 - Raisins - Introduction of the Goth Kids s09e11 - Ginger Kids - Ginger kids s10e06 - ManBearPig - Excelsior! s11e04 - The Snuke - A snuke up the snizz s11e07 - Night of the Living Homeless - South Park's homeless problem s11e14 - The List - If it pleases and sparkles s12e14 - The Ungroundable - Goth Kids vs Vamp Kids s14e10 - Insheeption - Mr Mackey's hoarding problem s15e03 - Royal Pudding - A Canadian royal wedding! s15e06 - City Sushi - Say herro to the Tower of Peace s17e07,08,09 - Game of Thrones trilogy - The prequel to the game

Having played the game, I'd agree with this list.

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