A phrase commonly used by professional basketball player Rasheed Wallace; once famously yelled by coach Flip Saunders.
"Ball don't lie" is said when a player misses one, two or all three of his free throws after a questionable (read as: bullshit) foul call is made by an official. The ball is, essentially, the unbiased judge who will not reward the player by going in if the apparent foul was indeed bullshit.
*Andrew Bogut locks arms with Rasheed Wallace and trips over his own feet, prompting a foul call from the referee*
Rasheed: That's BULLSHIT, man!
*Andrew Bogut toes the line and proceeds to miss his first free throw*
Rasheed: BALL DON'T LIE!
*Bogut then attempts a second free throw and misses again*
Rasheed: BALL DON'T LIE, DAMNIT!