You do not want to do anything drastic to strain the relationship with your mother. She may seem crazy, but living under a roof with a seemingly crazy person is better than living on the streets.
However, I do think that your mother acted very irresponsibly. I would let her know that. I would tell her that you disagree with how she handled the situation, and that you feel that she overreacted. DO NOT DESTROY/SELL ANY OF HER PROPERTY. You need to act like the perfect son at home, not a jerk. You should remain calm and rational at all times, and hopefully she will come around. If you don't yell at her, or challenge her, she will have little ammunition with which to attack you with.
If this teacher is after you, I would talk to him. Remember, always remain calm/rational. If you are well behaved and abide by the school rules, the teacher cannot punish you, and if he does, he will look unprofessional. Apologise for the entire calculator incident, admit that it was stupid, and promise to be more respectful in his classes. Also, let him know that his decision to call your mother has inconvenienced you a great deal. Remain calm/respectful throughout.
(EDIT)Do not do this during a lesson/in front of a class - you do not want to embarrass him, and he may become threatened/defensive(EDIT)
If this fails, I would visit the Headmaster/Principal, and tell him the whole story. And I would not do this in passing, actually schedule a meeting with him, so that his full attention is on you. Explain that the entire episode was indeed your fault, and that you take full responsibility, but state that you feel that the situation was handled poorly. Find out the school's protocol for calling parents - does the teacher need permission, is it reserved for certain offences. If there was no threat of suspension, and your punishment was not an afternoon or saturday detention, then explain that the offence was not considered too serious, and that you felt it inappropriate that your mother was contacted. Also explain that you were severely/unfairly punished at home as a result of the phonecall.
If your teacher is out to get you, perhaps the Boss can look into it. The teacher, knowing that he is being watched, will not punish you so severely. N.B: This will only work if you do not misbehave at all. Be the perfect student. Do not even call-out in class, because you know that he will be weaiting for an opportunity to bust you.
[Honestly 'though, I think you did quite well not to scratch the hell out of the paint-job of the car whilst trying to put your gear in there.
I would have put the gear on the driver's seat, so that she'd have to move it herself.
And I would have destroyed the gear so that she couldn't sell it,"IF I CAN'T HAVE IT, NO ONE CAN!!!"
:scowl: