Something that you say out loud when someone is
bullshitting you, or when you simply don't believe what the fuck they're talking about. Beware, for the
bullshitter (aka challenge-artist) may be sneaky about it by slightly tweaking the story/comment to increase their cool-meter. You may also throw out
a red flag (like in the NFL) if you have one handy, at the moment that the bullshit is dropped on you. You will find that the same people are constantly "challenged", because they like to live lies, and they feel better about themselves by making up stories about something 'cool' that they did, or something 'cool' that happened to them.
Example:
1.
Nick: "What's up, how was the club last night after I left?"
TJ: "Oh man, you
shoulda stayed...right after you left, I hooked up with like 8 chicks, and they all came back to my place!"
Nick: "CHALLENGE!"
2.
Danny: "Yo kid, I just drank a whole
bottle of Jack!"
Chorus: "CHALLENGE!"