Passover is a week-long celebration of the Jews' liberation from slavery in Egypt. It's one of the most significant holidays in the Jewish calendar, and there are symbolic foods that are used in the Seder meal that is part religious service, part ritual meal. There are also traditional foods that families enjoy during the celebratory meal afterward. Both of these meals are big, elaborate gatherings that involve lots of cleaning and cooking for days in advance.
I'm not Jewish, but am familiar with the foods and the preparation from friends. The ceremony that surrounds the meal is really beautiful; it involves reading the story of the Jews' escape from slavery, a series of prayers and questions, and eating foods that symbolized the plight of their ancestors under the Egyptian rule.
And, of course, the traditional family meal sounds like a fantastic celebration. While some of the traditional foods, like beef brisket, are less than healthy, you can always try alternatives as long as they fall within kosher dietary restrictions, some of which become more strict at Passover (for example, no chametz, or leavening, is allowed).
Roast chicken is traditional and very healthy; you can also sub in salmon cakes for gefilte fish. Chicken matzo ball soup is delicious and comforting and can be "healthied up" with the inclusion of lots of vegetables. Charoset, with its mixture of fruits, nuts and honey is pretty healthy as well and can be incorporated into cakes for dessert. Some strict interpretations of Jewish law mean that people forgo most grains for the seven- or eight-day Passover period, which means using potatoes and matzo meal as starch.
Chabad.org has an extensive collection of healthier kosher-for-Passover recipes, from healthy versions of traditional foods to whole foods menus that re-imagine them entirely.
Do you celebrate Passover? If so, what are you cooking?