Rosh Hashanah is the beginning of the New Year on the Jewish Calender. The above artwork is both amusing and informative. (I found it here.) Another great source of information about this and other Jewish holidays (all things Jewish, really) can be found here.
Rosh Hashanah 2014 begins at sundown on September 24 and ends at sundown on September 26. So, yes, Happy New Year! In September!