I'm tired of my parents?

Okay so my parents and my family are going to our beach house this weekend for the fourth of july so all my siblings get to bring their friends, what do i get to do, STAY HOME WITH MY GRANDPARENTS. i HATE my family, they make me feel like the stupid step child and by not letting me go gives more room for their friends to go! This is so unfair! I feel like stupid cinderella! theyre making me take care of the animals and plants! Im 14 and a boy i want to go to the beach!! And when i told my parents i wanted to go they said "you dont have a life so you can stay here" !! WTF!! I have the most chores and everything. Ugh I swear im secretly a stepchild. What should I do to make them let me go?