The act of partying all day Thursday and knowing you have the next day (Friday) off to relax and do whatever you want. As madefamous 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 day Thursday.
A Bon Jovi Friday is were you slack off the day before Friday and partytill 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!"