Rosh Hashanah

A shofar or ram's horn is used to summon Jews to Rosh Hashanah services. A reference to this holiday from Leviticus 23:24-25 mentions the horn, but not the name of the holiday:

24: Speak unto the children of Israel, saying, In the seventh month, in the first day of the month, shall ye have a sabbath, a memorial of blowing of trumpets, an holy convocation.

Rosh Hashanah, the Jewish New Year, falls on the first and second days of the Jewish month of Tishrei. 10 days later is the Day of Atonement or Yom Kippur.

In the Jewish Calendar, this is the first day of the year 5773. Rosh Hashanah runs from sunset September 16, 2012 to nightfall September 18, 2012.

2 Jewish New Years - Rosh Hashanah and Passover
Try the Rosh Hashanah Quiz. It is based entirely on this blog post.