I'm a sucker for shows meant for teenagers (Secret Life of an American Teenager, Greek, Pretty Little Liars, etc) Funnily enough, all the ones listed are ABC Family shows. I love that channel. The newest addition to my DVR schedule is The Lying Game.
It's based on a series of books by Sara Shepard who also wrote the Pretty Little Liars books. Here's a synopsis according to Wikipedia:
"Set in Phoenix, Arizona, the series is about Emma (Alexandra Chando), a foster child who finds out she has an identical twin sister, Sutton (also played by Chando). Both girls were separated at birth with Sutton being adopted by wealthy parents and is seemingly living an ideal life. Meeting prior to the pilot episode, Sutton talks Emma into stepping into her life for a few days while she pursues their birth mother in Los Angeles. Initially excited to do this favor for her sister, Emma soon learns that Sutton has many hidden secrets. Now, Emma must continue to cover as Sutton while Sutton continues her search for their birth mother."