Today is Groundhog Day and it also is the Chinese New Year and the cartoon character, Vitinho, anniversary. But Google does not have a logo for Groundhog Day, Bing does, so does Dogpile and some other places. Google Hong Kong has a logo for the Chinese New Year and Google Portugal has a logo for Vitinho.
Here is a collection of the logos...
Groundhog Day Logos:
FourSquare (Special Badge I unlocked):
Search Engine Roundtable:
Chinese New Year at Google Korea:
Vitinho Logo at Google Portugal: