Bar/Bat Mitzvahs start the day with their ceremony at the synagogue, and then meet up in the afternoon or evening at the big party, highlighted by the hora dance.
The hora, which is danced usually to the music of "Hava Nagila" is a big deal that kicks the Bar/Bat Mitzvah party into high gear and is usually followed with dinner, games and more dancing.
The Hora is said to have begun in Romania, and was adapted by the Jews in 1924 when it was performed by Baruch Agadati.
Wikipedia: "To start the dance, everybody forms a circle, holding hands or interlocking arms behind their backs or on their shoulders and steps forward toward the right with the left foot, then follows with the right foot. The left foot is then brought back, followed by the right foot. This is done while holding hands and circling together in a fast and cheerful motion to the right."
That's the long version--the short--everyone gets together in a circle, links arms and dances, with the honoree and his or her family by their side. The DJ barks out the instructions, and the dancers follow as instructed.
These photographs were taken by Graham and Graham Photography in Los Angeles, at the Annenberg Beach House in Santa Monica, and the Ayres Hotel near Manhattan Beach.