Please help me? I have absolutely nothing to do during the Summer?

Hi, it's the annual summer break... but I have virtually NOTHING TO DO. All during the week my dad doesn't want people or friends at the house while he and my step mom are at work, so I sit and do nothing. All I do is lie around like a slob and only watch T.V., go on the internet, play my DS, and now read. It makes me upset, because I only hang out with a couple of people and only sometimes over the weekend (If I'm not visiting my mom). I'm getting no exercise either since I have no one to go outside with. My bro is always at his friends house or bowling, so he's out a lot. I want to hang with my own friends during the week but It seems wrong to ask to go to their house and get a ride from them. What the heck should I do? I feel like a piece of crap who sits in their pajamas all day because I have nothing to dress up for... and I mean ALL WEEK, not just the occasional day. Please help with some ideas...