Dude2: Nah man, my Econ professor is reviewing the shit that's gonna be on the final.
Dude1: Don't be such a boring nerd, carpe diem! That's how I roll and my life is awesome.
Dude2: Dude I party every fucking night and I always go home with a hottie. You're flunking out and you can't get laid to save your life cause everyone knows you're a loser. Fuck carpe diem, man. Carpe noctem is where it's at.
Dude1: Whatever man, YOLO.
It is a pun off of Carpe Diem. Which is a Latin expression, meaning 'Seize the day'.
Guy 1: Hey, shouldn't you be sleeping?
Guy 2: Carpe Noctem, man. I will when I level up my guy.