There are many traditions and customs which are, today, observed throughout the Jewish world, which have their origins in Tzfat:

Kabbalat Shabbat -- Kabbalat Shabbat service, sung at the beginning of Shabbat, was instituted by the ARI and his students.  They would go to an apple orchard outside of the city and sing hymns and psalms and R' Alkabetz's L'cha Dodi, as they watched the sun set over Mt. Meron and "brought in" the Sabbath.

Upsherin -- A kabbalistic tradition exists of leaving a little boy's hair uncut until age 3, as the child "ripens", in the same way that a fruit tree's fruit is only picked after the third year.  At age 3, many people take their young boys to the tomb of R' Shimon Bar Yochai (believed to have written the Zohar, basis of Kabbalah)at Mt. Meron to have their hair snipped, often by great rabbis and rebbes.  This was begun by the ARI as a blessing to the boys and their families for long lives of health and happiness.

Tu B'Shevat Seder -- Mentioned in the Talmud, the "New Year of the Trees" (when the sap begins to run in the trees in late winter) is a time when Jews recognize their dependence on nature and appreciation of the environment.  The ARI and his students instituted a "Seder", modeled on the Passover Seder, where, in order, each of the Land of Israel's seven species is discussed, and thanks given for what that species gives us. 

There are many other discussions during the Seder about the different meanings of various fruits and wines. 

Tikkun Leil Shavouth -- One Shavouth night as R' Shlomo Alkebetz and R' Yosef Caro sat studying Torah, R' Caro's maggid, his heavenly messanger, related to him that from this holiday onward, Jews should make it their custom to do exactly that....spend Shavouth night awake, studying Torah.  Till today, Jews do this, known as the Tikkun of Shavouth. 

Lag B'Omer Procession to Mt. Meron  In the 16th century, the ARI initiated the traditional Lag B'Omer procession from Tzfat to the gravesite of R' Shimon Bar Yochai at Mt. Meron.  R' Bar Yochai was the first recognized scholar of Kabbalah, and the author of the Zohar, the book of Kabbalah. 

In the 19th century, the Abu family added the tradition of bringing the Torah scroll from their house which would accompany the pilgrims to Mt. Meron with singing and dancing....this ceremony is the official opening ceremony of Lag B'Omer today.