when something becomes really popular and/or cool.
Skateboarding is so hot right now.
Ryan Cruze? So hot right now.
when someone is odd or does something odd; saying it to/about someone who really isn't hot; making fun of someone
*fat lady trips on the bus stairs*
person 1: SO HOT
*your mother cursing in english with an accent*
person 1 & 2 in unison: SO HOT