15k

A common term used by Marines (USMC) to refer to something/someone/some unimaginable situation or feat as ridiculous or, lamely speaking, "Bullshit"

"Yo Devildog, I'm getting NJP'd tomorrow!"
"Really! Sorry about that Devil, That military underage drinking law is 15k."

"Damn! This '15 minutes prior' shit is 15k!"

15K run

A life-threatening amount of gay anal sex.

"Holy shit, I just went on a 15K run. I'm sweating and panting so hard right now"