My problem: my car, a Saturn Ion (which I do like! it is a 'super low emission' vehicle and gets great gas mileage) all of sudden, out of the blue, would not turn off. Yep, wouldn't turn off, as in the key would not physically turn to the off position (which is pretty much unlike any car problem I've ever had). After much swearing and pounding on the steering wheel, it was determined (by a phone call to Saturn) that the only way to turn it fully off was to disconnect the battery, which is a colossal pain in the neck.
What the internet said: After I unhooked the battery, I immediately googled it (obviously). I found a lot of stuff about this, apparently it is a known problem, and according to the many people who are angry about it on Consumer Affairs, it can cost a ton of money to fix it at the dealer or a mechanic, because they replace the entire ignition. This seems to be how most people are solving this problem. Obviously, this was depressing, until I saw one guy in the middle of the list of complaints claiming to be a locksmith, saying that he's fixed a lot of these himself without replacing anything. I was intrigued, and called a nearby mechanic, who is apparently super awesome and honest to see if he could help me or tell me what to do. He told me it is a common problem, and not to take it to him, but just to take it to an automotive locksmith he recommended (see? awesome and super honest).
The solution (listen up!!): DON'T pay hundreds of dollars to replace anything big if you have this problem. This is what a mechanic will do, because they'll see something about the place the key goes in is broken but won't know if its something else with the ignition, and will replace the whole thing. BUT, the problem is typically that a spring (or something) pops out and a tumbler gets out of place in the lock so the key can't turn. The locksmith had to work on my car for a few hours, but ultimately managed to save the lock and repair it. It still wasn't cheap to pay for all that labor, but it was waaaaaaaayyyyy less than the numbers the other customers were throwing out on the website I found. I couldn't find anywhere on the internet telling me to do this, so, here you go, internets, this ones for you.
(here are search terms I tried to use to help me fix the problem, which I'll just put on here in case it'll help someone else find this hint!
Saturn ion won't turn off
key won't turn
Saturn ignition problem
Saturn key stuck in lock
Saturn key problem
car key stuck
can't get key out of ignition
help! )