I have a Saturn wagon. Last summer I talked about a problem where it wouldn't let me put the key into the ignition, and how I solved it at the time. An additional followup to that: after a while I discovered that I could get the key into the ignition if I just banged on the steering column from underneath. That was much less tiring than the wrestling I was doing.
Nowadays I'm not having that problem anymore - it magically vanished after I had a bunch of unrelated problems fixed at a place other than the Saturn dealership. (Incidentally, to follow up what happened there - the epilepsy was due to a jammed door lock switch. They replaced both, everything is working great now.) Did the ignition problem vanish because they found and fixed it too? Or is it just due to a change in the weather from summer super-muggy hot to late fall "reasonable"? I don't know.
Why am I writing this post? Because someone googled on "Saturn car key won't go into ignition" and only found my post about Saturn customer service. I thought I'd be helpful and link in every part of the whole saga. :) For the executive summary: try banging on it from underneath.