A cousin has recently gotten in the habit of saying
"that's what's up" as an answer to almost anything.
Me: The weather sure is nice today.
Him: Yeah, it is...that's what's up!
Me: I like your shirt.
Him: Thanks cuz....that's what's up!
Me: We're having chicken for dinner tonight
Him: on yeah? That's what's up!
He will also follow it up with "no doubt", or sometimes just "no doubt...that's what's up"
I wanna smack him up side his head when he does that! It's annoying as heck. he's in the military, so I'm not sure where it came from.