Uso Da
Uso Da is Japanese for "That's a lie." It's often screamed by characters from Higurashi no Naku Koro Ni, who really love this phrase. Make sure that if you use it, you yell it really loud.
"What's up man? Somebody told me you were cheating on your girlfriend last night."
"USO DAAAAAA!"
"Calm down, man, what do you think this is, anime?"
"USO DAAAAAA!"
"Calm down, man, what do you think this is, anime?"