This is a problem I ignored for a while about 6 months ago. Normally I could wiggle it and it would turn. Well, eventually it simply refused. I tried for 30 mins or so, even added WD40 (which I had in my trunk this having happened before).

Well, as always it was at the worst time. I called the DC Roadside assistance and they showed up. The wheels were locked and not straight so they had to bring in another tow truck that could lift the car rather than pull it. I left them alone (in retrospect that wasn't very smart). Eventually they get it lifted and to the dealership. The next problem was how to get it off the truck and into a bay. I didn't get to see it, but the dealer told me they used some sort of industrial lubricant and pulled/pushed the car into a bay.

The fix in the end was to replace the whole key/ignition cylinder and it's been great since then.