Something comedian Nick Swardson says all the time... and a lot of people have started to use as a response to everything... and it usually never fits the situation.
party.
The exclamation used by Sixth Form students, whenever they hear something that brings them joy, usually the likelihood of a booze-filled houseparty coming up, and they need to express that joy to everybody else present.
McLameass: I'm having a party tonight y'all!
Jordyn: AHHH! LOVE THAT! PARTY!
Peter: Is there a party going down?
Jordyn: YEAH!
Peter: PARTY!