So Little Time Series by Megan Stine

Good-girl Chloe needs to find a way to land in detention with her heartthrob — bad boy Travis. But every time she does something wrong, the vice-principal blames someone else. Soon the whole school is mad at Chloe. And when she finally gets detention, Travis's time in detention is up! Meanwhile, her sister, Riley, has decided to give geek Larry a chance at romance and agrees to a study date with him... moreGood-girl Chloe needs to find a way to land in detention with her heartthrob — bad boy Travis. But every time she does something wrong, the vice-principal blames someone else. Soon the whole school is mad at Chloe. And when she finally gets detention, Travis's time in detention is up! Meanwhile, her sister, Riley, has decided to give geek Larry a chance at romance and agrees to a study date with him. But after some humorous mishaps, she realizes the whole thing was a big mistake — Larry really is as weird as he seems! less

Don't get mad when your sister borrows your new outfit.Don't get mad when your sister doesn't pick you for her team.Don't get mad when your sister forgets to give you phone messages.Don't get mad -- get even!Chloe and Riley Carlson ... so much to do ... so little time.