Speaking of messed-up jaws, if I open my mouth wide enough (for instance, if I yawn) sometimes my right jaw joint will lock in place and I won't be able to close my mouth unless I basically punch my jaw back into place. One time it got stuck for an hour before I could fix it. Freaked me the hell out.
If it keeps doing that, or gets worse, you might want to get it looked at. Sometimes a tendon or ligament needs tightening, or something's shifted that things aren't sitting square in place anymore.
That happens to me too. I went to doctor a long time a go but all she did was give me some instructions for excercising my jaw.
Now if I ever bothered to do those then it might actually help...
My jaw basically dislocates whenever I open it too much and although it hasn't gotten stuck, more than a few times years ago, closing my mouth happens in a weird fashion as my jaw does a z shaped movement to get past the point where it would get stuck. I had been doing that for over 20 years before I even realised it. It just seemed natural for me that my jaw does a *crack* sound and those movements.
In hindsight someone in my family should have noticed it earlier if not me.