I cant believe this worked!
I was in the process of locating a tow-service to tow my Jeep to get the ignition cylinder replaced when I found these old posts. A few days ago, the key for my 99 TJ Wrangler just stopped going all the way in and would not turn the ignition. Although the steering wheel was not locked, the key would not go all the way in and turn the ignition. I read this post, and put a dishtowel over the key in the ignition and gave it a few raps with a hammer.. It turned! It still sticks and prob needs to be replaced/fixed, but at least I can DRIVE IT to be fixed and not tow it.