I love our Maslenitsa holiday in Russia! It marks the end of winter and has a long history with many curious traditions. For example, we have a week of festivities to celebrate this holiday here. People cook traditional dishes (blini - Russian pancakes), have cozy family gatherings, enjoy some outdoor activities. The most fun thing to do during this time is the burning of an effigy of Lady Maslenitsa.
If you want to wish someone happy holiday, you need to write: "Весёлой Масленицы!" or just "C Масленицей!".