Need to solve issue with mom, shes haring me to stop playing the computer?

I'm 15, upcoming sophmore in highschool, I go to a college prep school, very hard and make straight A's. I am not a nerd or geek, just a normal guy who likes to play WoW (mmo). Now that it's summer its MY TIME to relax and enjoy what I like to do over these SHORT 2 months. here I am exercising, going to movies with friends, and fit in a 5-8 hours of gaming a day.. just because im bored, too young for a job and cant be busy all day long etc. My mom hates excessive TV watching/gaming etc.. She jumps on my *** all the time for playing.. she argues with me and WONT LISTEN TO ME WHEN IM TALKING, she thinks she knows everything.. I try to imply im a good kid and am not out doing drugs or drinking, rarely get in trouble and should have some time to relax. She never lets me get a point in and just GOD , pisses me off.. How can I get her to lay off, I sware all she does all day is think about me and what im doing.. Any advice as to what to do?