Eva's first joke

It's an exciting couple of days in the Viciana household, as Eva has decided to tell her first joke. It goes a little something like this:

Knock knock
(who's there?)
Orange
(orange who)
ORANGE BOY!
(insert Eva's uncontrollable laughter here)

Nope, we don't get it either!

Here's the other one she likes:
Knock knock
(who's there?)
Party Hat
(Party hat who?)
PARTY HAT VICIANA!