The High Holy Days can be one of the most challenging seasons for interfaith families. Unlike services during the rest of the Jewish year--which are often much more informal and personal--the liturgy, theology, language and prayers of the High Holy Day season are usually the most difficult, anthropomorphic, and uncomfortable of the year for most Jews.
The primary images of God throughout this sacred season are of a deity who judges our actions, encourages us to repent and change direction, and then decides our fate for the year ahead. Many people, Jews and non-Jews alike, find the ancient images of God as the "Divine Judge sitting on the throne of Judgment" and the prayers which ask "Who shall live and who shall die," along with their long list of all the gruesome ways that we might perish in the year ahead, difficult to relate to and disconnected from their own spiritual search for meaning, purpose and personal growth in life.
This is why one of the great ironies of interfaith life is that so often the very first exposure that a potential non-Jewish life partner has to Judaism and Jewish rituals is when his or her Jewish partner brings him or her to a High Holy Day service. It is probably the single worst possible way to introduce anyone to what Judaism is all about, and without a key to the liturgical drama that is going on, perhaps one of the most difficult ways to understand the values, ethics, and meaning that Judaism has taught the world for the past 4,000 years.
Having said that, if you are going to bring a non-Jew to the High Holy Days I would suggest that one such "key" to the liturgy is to prepare them in advance for the kind of prayer language they will be encountering. Let them know that the image of God in the High Holy Day prayer book is specifically depicted in the most dramatic form possible (God as supreme "judge" of our actions, sitting on the "throne of Justice," deciding "who shall live and who shall die" in the year ahead) to lead us to a personal process of self-reflection and judgment so that we will take this time to examine our own actions of the past year and make decisions about the kind of person we want to be and how we want to act in the year ahead.
In spite of this challenging introduction to Jewish theology, interfaith couples continue to get married or make life commitments, and then the non-Jewish partner becomes a "Jew by association" and his or her celebration of the High Holy Days then becomes part of the greater experience of the Jewish partner's extended family. Since Judaism is a civilization with all the complexity that any civilization has (language, literature, art, culture, foods, music, religion, homeland) and not merely a "religion" in the narrow definition of a system of shared beliefs, it is in these broader areas of Jewish civilization that interfaith families often have their best shared holiday experiences.
For example, eating the ritual foods of the High Holy Day season together can provide any interfaith couple or family with wonderful opportunities to have positive experiences where the values are shared and the rituals are fun. Dipping apples in honey on Rosh Hashanah symbolizes the wish for a sweet new year. Taking a bite of the traditional round challah (my favorite is with raisins) can be seen as a symbol of the desire to bring wholeness into our lives and celebrate the cycles of life together. Fasting on Yom Kippur can remind us of the millions of children in America and throughout the world who don't get to choose whether or not to go hungry each day. All of these can become positive, powerful Jewish experiences that any interfaith family can embrace.
Second, many of the spiritual themes of the High Holy Day services themselves can provide inspiration for personal spiritual growth and reflect universal ethics and values that interfaith couples and families can embrace. For example, since Rosh Hashanah is celebrated as "the birthday of the world," it is a perfect time to remember our responsibility as stewards of the earth. Any family--whether same faith or interfaith--can make a difference in the world through our personal use of energy in our homes and throughout our lives. We can change regular light bulbs to environmentally friendly ones, make better choices about how, when and what we drive on our highways, eat less red meat, and make our homes, work and communities more sustainable in a hundred different ways. All of these choices and more can be seen as examples of the religious obligations ("mitzvot") that the High Holy Days teach of taking responsibility for our own actions and the world in which we live.
Third, it is important for interfaith couples to remember that one of the ways we demonstrate respect for our loved ones is by allowing them the freedom to choose how and when they wish to participate in religious ritual and tradition. If non-Jewish spouses or partners would prefer not to sit through Yom Kippur service--whether because the liturgy itself is uncomfortable or they simply don't relate to the pomp and length of the services--their Jewish partners should give them permission not to attend. Instead the Jewish partner can go to services with family members or friends and find other ways to "share" the holidays with their partners, such as being together for dinner at the beginning of the holiday or joining together for a break-fast.
These are just some of the many ways that interfaith couples and families can successfully celebrate the most sacred time of the Jewish year together in peace and harmony.