Marmalade Boy is a great anime. The story is about a girl named Miki with very strange parents. When her parents meet another couple, things get weirder as she suddenly now has two new step-parents and a new step-brother. But she has a plan. She and her "new brother" will put a stop to this ridiculous plan to divorce, switch partners and remarry. Problem is, her new brother doesn't seem to care! And no one told Miki that Yuu was so good looking. So in addition to her strange parents, Miki now has to deal with strange step parents, Miki has a new step-brother she has a crush on yet can't figure out, and now her long time crush finally confesses his love to her! You think this is a lot, wait til you get past these first few episodes.
Now, after you watch the entire series (no cheating on this), find the Marmalade Boy movie. This movie shows Yuu's reaction to the news about his parents' plans to swap partners and shows his first meeting Miki from his Point of View. I say to watch the series first, because this movie gives you a new prospective and you'll enjoy watching the series the second time as you'll finally see what Miki doesn't. But as I said, don't cheat. The series is a lot of fun when you are as lost about Yuu as Miki is!