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."
"Calm down, man, what do you think this is, anime?"
A phenomenon that can be observed in people who listen to music with headphones while walking. The affected person will walk perfectly in time with the music they are listening to- often more quickly or slowly than they normally would, depending on the tempo of the music. They will oftentimes not even notice that they are doing this. To everyone else, they simply look as if they are either in a huge hurry to get somewhere or are incredibly tired and can barely walk. Rhythm Walking can affect virtually anybody, and is more common in people who listen to music with a pronounced drum beat.
"Hey, what's up with Frank? He was shuffling along really slowly just a minute ago, and now he's walking really fast."
"He's got headphones in. Must be rhythm walking."
Slappin' the Grimlock is the coolest new activity you can do. Any hip new "thing" can be referred to in casual conversation as Slappin' the Grimlock, in order to confuse other people- the point being that if you have to ask what the other person means, you'll never be cool enough to partake in the activity.
"Hey man, me and my buddes are gonna go slap the Grimlock for a while, you wanna come?"
"The hell are you talking about?"
"Never mind... I guess you're just not cool enough to enjoy a good session of slappin' the Grimlock."
China Syndrome is when you connect to the Internet through a network that constantly tightens up its network policing policies, blocking more and more sites as time goes by. Named for the Chinese government's infamous crackdowns on forbidden sites.
"Man, this is bullshit. My network at work just started blocking 4chan!"
"That's the fifth site they've blocked this month! Sounds like your company's got a case of China Syndrome."
In fandom, a Little Black Dress is a character who someone feels can be "shipped" (paired up in a relationship) with virtually any other character. A Harry Potter fan whose Little Black Dress is Hermione would not only read Ron/Hermione fanfiction, but also Harry/Hermione, Snape/Hermione, Ginny/Hermione, and so forth.
"How can you read that story? It's freaking Voldemort/Hermione!"
"Hermione is my Little Black Dress. She goes with everything."