Late February or early March: Carnival in Brazil and others. The precise date of carnival is 7 weeks before Easter, which is moveable itself (the first full-moon Sunday after 21 March). Instead of relying on your own astrophysics skills, take note: Ash Wednesday for the next years will be 01 March 2006, 21 Feb 2007, 06 Feb 2008, 25 Feb 2009 and 17 Feb 2010.
Thursday before Ash Wednesday: Fasnacht in parts of southern Germany and Northeastern Switzerland - Colourful street carnivals to ward off the winter spirits, featuring costumed brass bands. Takes place in most towns