Why is 'misod chachomim unevonim' sometimes said and sometimes omitted in the repetition of the Amidah?
In Askenazi communities, the piece beginning 'misod chachomim unevonim' is said at the repetition of the Amidah at Shacharis when there are piyuttim (except Purim) and on Musaf on Yomim Noraim as well ...
The "Tefilat Geshem" ("Prayer for Rain") recited on Shemini 'Atzeret contains six verses. Each verse refers to a different person (except the last, which refers to a nation) and makes various ...
I don't know if they are technically called "piyutim", but there is a nusach we say on Rosh Hashana/Yom Kippur between "Ata Kadosh" to "Hamelech Hakadosh". Was that decreed by the Anshei Knesses ...