Shabbat Hagadol Shalom
Instead of the usual "Shabbat Shalom" that Sephardic and some Ashkenazic Jews wish each other every Shabbat, for this Shabbat of the year, one is supposed to wish each other "Shabbat Hagadol Shalom".
Of course, one of the reasons it's called Shabbat Hagadol is because of the use of the word "Hagadol" in the verse read in this week's Haftarah:
הִנֵּה אָנֹכִי שֹׁלֵחַ לָכֶם, אֵת אֵלִיָּה הַנָּבִיא--לִפְנֵי, בּוֹא יוֹם יְהוָה, הַגָּדוֹל, וְהַנּוֹרָא.
Eliyahu Hanavi, according to tradition based on this verse, is supposed to herald in the Ge'ula, among other End of Days tasks. Here is Aharit.com's (Hebrew) great list of what Eliayhu's role will be during the Ge'ula - complete with footnotes.