There are many elements which make the High Holy Days a unique experience. Often, congregations swell to double or triple their usual size, the musical settings of even common liturgy are different, and some might alter their dress by wearing either traditionally all-white garments or more formal wear than they would sport on Shabbat. Some congregations even have unique garments to dress their Torah scrolls in white.
On Yom Kippur, we share a holiday meal called seudat mafseket, the concluding meal before the fast begins. We begin the meal with haMotzi, the blessing over the challah