Growing up, my family often went apple-picking after Rosh Hashanah services. My Jewish New Year memories are intertwined with the cidery scent of apples rotting in the grass, the sound of bees buzzing, the long angle of late New England sun, and the brisk air that meant the excitement of new school clothes.
In autumn, our interfaith community celebrates Rosh Hashanah, Yom Kippur (the Day of Atonement), and the harvest festival of Sukkot. It may, in fact, appear that we are giving Christianity short shrift, because the “must do” Jewish holidays are stacked up front. When prospective members come to check us out in the fall, the Jewish partner in the couple tends to feel perfectly comfortable. If I can, I give those Jewish partners a heads up that as winter approaches, they will need to reckon with Christianity.
After a transition through the mostly secular Thanksgiving period, we shift into what I think of as our Christian season, with Advent and Christmas. We celebrate Hannukah of course. But since Hannukah is not actually among the top five Jewish holidays in terms of importance, we don’t attempt to give Hannukah and Christmas equal weight. “Being both” is not about distorting either religion to create false equivalencies. We do not have a Hannukah bush, or menorahs on our Christmas tree. Instead, we celebrate Advent and Christmas with as much historical integrity and spiritual depth as we can muster, to offset the commercial Christmas so prevalent in American culture. Jewish partners learn to accept, or not, seeing their children light Advent candles, sing carols, and talk about the birth of Jesus, that nice Jewish boy.
In spring, “being both” comes to a head with the twin week-long celebrations of Passover and Holy Week. Most interfaith families know this as the season of true “interfaith dilemma.” Jews are forced to confront the idea of resurrection. Christians are forced to confront the historical anti-Semitism associated with Easter. Everyone in the family must negotiate the “chosen people” language embedded in the Passover Seder, and the horror of the drowning of the Egyptians. And we must be nimble diplomats to avoid making a mishigas of meals with extended family featuring Easter buns, matzoh balls, ham and brisket.
With the end of the school year, our interfaith community goes into sleep mode, as do many religious communities. For some strange and convenient reason, there are no major holidays in either Judaism or Christianity during the summer. Instead, many of us use this time to reflect on whether or not we will recommit ourselves to the communities we have chosen—especially those of us who are wandering Jews, wandering Christians, or both.
Susan Katz Miller is the author of Being Both: Embracing Two Religions in One Interfaith Family, from Beacon Press. She works as an interfaith families consultant, speaker, and coach. Follow her on twitter @beingboth.
Being Both 
I see Passover and Easter as the Jewish and Christian holidays that are simultaneously most similar and most different.
Both are stories of sacrifice and redemption. The Crucifixion events took place around Passover and incorporates Passover into its narrative.
But where the Crucifixion and Resurrection are (now) about a personal messiah, acceptance of whom allows the redemption of an individual, the Passover story for Jews is about national redemption, just as the Jewish messiah will be a national rather than a personal savior. Yet despite this difference, Jews are taught in the Passover seder to that the Exodus stories applies to each of us, personally: it is as if we, individually were redeemed from slavery in Egypt.
Oh, and both religions invoke a sacrificed lamb, one literal and the other allegorical, and other shared symbolic foods, namely eggs.
So similar and so different and so similar.
I am becoming more and more comfortable choosing my own way to honor the high holy days. IFFP has made that possible.