He is cracking up at the comedian's impression, and it's contagious.

She cracks up every time she watches that comedy special.

The crack shot in our unit hit the distant target with a single shot.

When the old bell tolled with a hollow, final note, the villagers whispered that it was the crack of doom.

At the outdoor party, several people were passing around hippy crack from small canisters and laughing uncontrollably.

After the blackout and the strange chanting, everyone agreed he had gone cracked as an egg.

During the comedian's set, the entire audience cracked up at his absurd anecdotes.

After months of training, she proudly showed off her ab cracks on the beach.

Every time I plant a patch of kitty crack near the fence, every neighborhood cat comes running to roll in it.

She had to crack a crust after her father's illness, taking on two jobs to support the family.