This happened to me, not in my '99 Intrigue but in my wife's 2000 Chevy Malibu. It was not because the steering wheel was turned almost to the lock, in which case a little jiggle of the steering wheel while turning the key will free it. I think it was a stuck tumbler in the lock mechanism. A little silicone spray (just a little) seems to have worked to keep it from happening again. Best technique is to spray in the lock, insert key, turn to "acc" position then back to off, remove the key and wipe it dry. Repeat three or four times. Good luck.