Purim is the celebration of Jewish deliverance as told in the book of Esther. Like all Jewish holidays it is celebrated according to the lunar calendar, and as such the date varies each year, but it usually falls sometime in March. For those in the know, it is celebrated on the or the 14th of Adar in the Hebrew calendar OR the 15th of Adar for Jerusalem and all ancient walled cites.
Key foods: Hamantashen
Passover is an eight-day celebration of the emancipation of the Jews from Egypt. For those in the know, it is from the 15th to 22nd of Nissan. This is a big food holiday, as one of the key elements is the Seder dinner.
Key foods: Charosset, gefilte fish, matzoh
Rosh Hashanah is the Jewish New Year, and usually falls sometime in September or early October. The celebrating is slightly more subdued than the American New Year, but it is one of the most observed holidays among American Jews. It occurs on the first day of the Hebrew month Tishrei.
Key foods: Apples, honey, challah
Yom Kippur is the Jewish day of atonement. A day of fasting and repentance, when Jews reflect on their sins and failings from the past year. It is a 25-hour fast that begins at sundown with a service called Kol Nidre and continues until the following evening. It starts on the ninth day of Tishrei. Although this is a fasting holiday, it is not uncommon for Jewish families to gather for a dinner to break their fast.
Key foods: Lox, whitefish, kugel
Sukkot is a holiday that commemorates the wandering in the desert of the Jewish people after their emancipation from Egypt. The tradition is to build a sukkah, or shelter in your yard to represent the transient existence of the biblical Jews. Meals are eaten in the sukkah, and some people choose to sleep in it too. Sukkoth begins on the 14th day of Tishrei.
Key foods: Kreplach, fall harvest foods
Chanukkah is well-known among non-Jews because it usually falls sometime between Thanksgiving and Christmas. Called “The Festival of Lights” it is an eight-night holiday that commemorates the rededication of the Temple in Jerusalem. At the time there was only enough oil to light the menorah for one night, but it would take eight days to make more oil, yet the lamp stayed lit the entire eight days. Traditions vary, but most Jews have a menorah and light candles for each night, and some give gifts, but this is mostly due to creeping traditions from Christmas. It falls on the 25th day of the Hebrew month Kislev.
Key foods: Latke and sufganiyot (jelly doughnuts!)
There are many other holidays, and I recommend reading about them here: