Scott Rabideau

Scrubs celebrates its 100th episode with an homage to The Wizard of Oz: Zach Braff directs - J.D. (Zach Braff) is called in to work on his day off and every time he tries to go home, he is pulled into another drama. Turk (Donald Faison) searches for a heart donor to save a dying patient; Carla (Judy Reyes) is worried that she doesn't have the courage to become a parent. Meanwhile, Eliot (Sarah Chalke) doesn't think she has the brains to lead a question and answer session on a subject she knows little about. All the while the Janitor (Neil Flynn) is trying to make the hospital easier to navigate by painting color-coded lines, including a yellow line, which leads to the exit. John McGinley and Ken Jenkins also star.

Brotherly love brings J.D. when his brother Dan comes back to town while Elliot and Carla begin moonlighting at a veterinary clinic; Tom Cavanagh Guest Stars. -- Dan decides to stay with J.D. for a while, since their mom's new fiancé kicked him out, but after spending some quality time with him at the hospital, Dan isn't sure if he likes the cynical person his little brother has become. Meanwhile, Elliot (Sarah Chalke) tries to deal with her own problems of having a long distance relationship and decides to try moonlighting as a pet examiner with Carla (Judy Reyes) to save up money to go visit her boyfriend as Carla saves up for her wedding.

Love is no laughing matter -- Mandy Moore guest stars -- J.D. (Zach Braff) becomes annoyed that new girlfriend, Julie (Mandy Moore), doesn't laugh, but rather tells him when things are funny. Afraid that he is going to screw up yet another relationship, Elliot (Sarah Chalke) encourages J.D. to start saying his feelings out loud and Turk (Donald Faison) tries to use his psychology background to fix the issue. Meanwhile, Carla (Judy Reyes) is upset when the Janitor (Neil Flynn) refers to the new nurse as a 'hot young Carla,' increasing her growing concern that she is too old to conceive. John C. McGinley and Ken Jenkins also star.