The mythical day of the week only achieved when you wake up drunk, and can not remember what day it actually is. Therefor, the only logical answer is Fruesday.
Person 1: *Vomit - Cough* ... I'm so drunk.. what day is it?
Mysterious occurrence amongst College Students in which Thursday turns into Friday and everyone gets fucked up regardless of having class the next morning.
Dallas: "Hey Caleb it's Thursday!"
Caleb: "You mean Fhursday right?"
Dallas: "What the fucks the difference?"
Caleb: "There is none...."