Crazy, mentally unstable.

To break, hack or "crack" a stupid-assed, expensive-beyond-belief, software program with a CD-ROM key code.

adjective used to describe something that only a person high on crack could imagine/come up with/create

Removing copyright protection from copyrighted software. Commonly used to obtain software without paying for it. Cracking is not by inserting a false or used serial number, but to insert other documents and files into the actual program to make it seem like it was registered by a paying customer, when it actually wasn't.

1) Unbelievable; insane.

2) Good, bad, or extremely out of the ordinary.

Note: Both definitions an be used in both positive and pejorative sense.

Basically, crack is silly, intentionally non-serious, and has a high tendency to be extremely crazy and unfounded, such as purposeful OOC-ness or playing on cliches, inside jokes, and/or fanon.

The term crack probably stems from crack as in crack cocaine, as opposed to a crack in a wall. As in, so horrendously unfounded/silly that only one could have come up with it while under the influence of crack.

To be completely destroyed. Usually in refrence to sports.