History and origin
Its origin may go back to the siege and destruction of the city of Rapperswil at St. Matthew in 1350 by Rudolf Brun, first mayor of the city of Zürich. At that time, compassionate citizens served food to hungry children through the windows of their houses, to which the current practice recalls.
As of today
After the traditional "Herrenessen" (dinner of the council members) in the Rathaus Rapperswil and cabaret program with distinguished guests, hundreds of children gather in the main square on Shrove Tuesday. At exactly 15:15 the windows of the town hall open and a fanfare sounds. A council member asks, “Sind alli mini Buebe doo?” (Swiss German: Are all my boys here?), and the answer is given: “Joo! Eis - Zwei - Geissebei !” (Yes, one, two, goat-leg!), whereupon sausages, bread rolls and Biberli (a sweet) are dropped down to the children on the Hauptplatz (main square). Following the so-called Austeilete, in the evening there is intense activity, and the crowning of the carnival, all Guggenmusik (carnival marching bands) gathered at Schloss Rapperswil to celebrate a roaring concert.
Media related to Eis-zwei-Geissebei at Wikimedia Commons