In Germany, you wish your friends and neighbours a „Guten Rutsch“ when you meet them on December 30th or 31st. 

 

It's not quite clear where the saying comes from.

 

Literally understood, “Rutsch”  means “slide”. So you are meant to have "a good slide into the new year".

 

Or maybe the saying comes from the hebrew/yiddish word “Rosch”, deriving from ראש השנה טוב Rosh ha-Shana tov ( = a good beginning, a good start into the new year).

 

Some people also say the German “Guten Rutsch” comes from the German word “Reise” (journey).