Bon Jovi Friday, originally, is a concept taken from "The Xtacles", where on the Thursday before a Friday you have off - you party and screw off at work like it is Friday.
However this concept has come to pertain to any such day that precedes a day or days off.
Although such days are still referred to as "Bon Jovi Friday" no matter the actual day of the week.
“When you have Friday off from work, and you just F*ck around all day Thursday … you know what that is? That is a Bon Jovi Friday!”
The act of partying all dayThursday and knowing you have the next day (Friday) off to relax and do whatever you want. As made famous by the show The Xtacles on Adult Swim.
"I have the day off tomorrow so let's have a Bon Jovi Friday and party all day!"
The day before you have Friday off and you slack off all dayThursday.
A Bon Jovi Friday is were you slack off the day before Friday and party till Friday is over.
"No, no, no you don't understand. When you have Friday off from work and you just f*%k around all day Thursday, you know what that is? That is a Bon Jovi Friday!"
"Bon Jovi Friday!"