From Generation to Generation: Video
There is a song called L'dor Va'dor (From Generation to Generation) that is often sung during the Shabbat prayer service. The verse from the song was taken from the Kedusha, which is the last prayer in the Amidah, the main prayer section in the service.
The verse says in English:
"To all generations we will declare Your greatness, and for all eternity proclaim Your holiness."
(Translation from Mishkan T'fila: a Reform Siddur.)
This verse could be proclaimed with authenticity by many family members who are not Jewish. It is important to know what the words to this song mean and how you and your relatives understand the phrase "from generation to generation." Joining in saying this verse could be a unifying experience for a family on Shabbat, and all the more so at a bar or bat mitzvah.
Hebrew for "prayer book," the plural is "siddurim."