How can i get my parents to give my game systems back?

My parents took away my xbox 360 and all my other game systems because of my grade in one of my classes (fine arts) They say I can't get it back until my grade is a 75 or above and I have a 72. Now its spring break and they still don't want to give it back. What do you think I could do to convince them? I have good grades in all my other classes.How can i get my parents to give my game systems back?
how about sincerely discussing the topic at hand, in a mature and responsible way, without shouting. ask them to explain in detail what you are meant to learn with no consoles and pretend to understand. if they think you have understood, they may change their minds as you have shown them you are a mature young man/woman. if your parents arent so easily manipulated, threaten to become emo and start dressing in black and kissing people of the same sex, cutting your wrists for a 'rush' and writing terrible poems. they will be so scared of your new rebellious nature they will give everything back to you.How can i get my parents to give my game systems back?
promise them that you will increase your grade when you get back to school..





maybe even try cleaning the house up a little, and doing some small chores without being asked





just remember that if you don't get your way, not to beg and plead because often it will end up worse .
do the opposite of what you did to get it taken away from you. Why do you have a C in fine arts? aren't those classes supposed to be the easy ones?
if my grades were as good as yours is right now my parents would buy me a 360