off the hook

Also slang: crazy; wack; fucked up; out of control

1. (said of a person)
   Absolved of blame or responsibility, or relieved of a duty. "I'm going to let you off the hook this time, but don't let me catch you doing it again."
    
2. (said of a telephone)
   1. Ringing incessantly, over a period of time. "Thanks to that misprinted ad offering 100% off, our phone has been ringing off the hook."
   2. Disabled because the handset is not properly seated on the base. (Older wall-mounted telephones literally "hung up" when the weight of the handset depressed a pivoting hook on the base.)