Shavuos -- Auspicious Time to ask for geulah!

Maamar Mordechai by R' Mordechai of Nedavorno (5660)

All agree that on Atzeres [Shavuos] the day is "half for you"...on Atzeres which is the time of receiving the Torah, and chazal refer to this as freedom from enslavement to the nations. This makes it the appropriate time for an eis ratzon to daven for the drawing close of the ketz of the geulah.