About the size of a dollar bill, the mud covered the carpet and spanned the crack of the trapdoor that led down into the three-foot-high crawl space beneath the house.

NPR: Excerpt: 'Killer Weekend'

When you - you're crack climbing a thin crack, you stick your toes into the crack and then kind of wrench down on to stand up, and it's painful.

NPR: Craig DeMartino: Winner in the Extremity Games

Mimicking that forced me down into a better fielding position and kept my view of the ball steady from the crack of the bat to the smack of the glove.

WSJ: Pro Ball Baseball Clinic Weekend

In 2003 he heard the tale of a cadre of crack engineers who had quit Cray Research, the old supercomputer maker, to explore bringing powerful features down to the world of cheap servers.

FORBES: The New Barbarians