Lance Armstrong -- 'Missing Testicle' Surfaces During Card Game

Sooooooo ... game night took a helluva turn at the Armstrong house this weekend.

Lance was playing "Cards Against Humanity" (it's sorta like competitive group Mad Libs) ... when he drew a card that hit a little below the belt ... "Lance Armstrong's missing testicle."

Lance had a sense of humor about it ... and posted a photo of the card on Twitter along with the caption, "Just another night of playing Cards Against Humanity."