I say "Huzzah!" all the time anyway. I didn't actually learn it from Cave Story, either, got it from Toadsworth in Mario and Luigi.
Anyway, here's some little phrases I might be able to sneak in.
"...the most basic X."
Replace any noun at random with "Puppyhat!" or "Curly's Panties" or the less risky "Chaco's Lipstick".
"Hey! If you've been really good this year, Santa might give you his Fireball gun!" Less effective since it's at April, but still might affect the young'uns a bit.
"You must know that I hold no love for this X. It is simply my fate that I X it." A bit modified, but useful for a variety of things.
"You're an X from the Surface, aren't you?"
Refer to all locations as the Surface, actually.
"Ooooh, we have a VISITOR!" Said in the most epic happy face you can muster.
Refer to all groups as Team 9.
Specifically wear a scarf. When asked why you have it in April, say you woke up with it. Bonus points if you're the sort to wear a tank top or a hat in those days.
"If you want to go through my fireplace, you're going to need a bit of Jellyfish Juice." Best said to random people, especially if you run away immediately thereafter.
All animals are now Mimiga. Except birds, which are now Sky Dragons, and actual rabbits and bunnies, which are now the Kanpachis.
"You're a nice person. And so strong!" Say this as monotone as possible.
When asked if you'd like something to eat, reply that you'll have some blue flowers.
"Doctor Dumb can go screw himself!" Refuse to elaborate on who Doctor Dumb is.
Ooh, and here's the crowner!
Carry around a tiny sign all day. When called out on your weirdness or unable to explain without spoiling things, take out the sign and hold it up until they leave you alone. The sign should have "•••" on it.
:3
