One of the many euphemisms for smoking marijuana, this one derived from The Lord of the Rings. Wizard time occurs when someone hits that pipeweed like Gandalf in the Shire. Wizard time may happen at 4:20 or any other time of the day or night because wizards are never late, nor are they early. They light up precisely when they mean to.
"Wanna go out for dinner tonight?"
"Nah, let's just order pizza and load up a bowl. It's wizard time."