I have three siblings; two brothers and one sister.
None of us are very close although my sister tries really hard and my eldest brother makes the attempt. My youngest brother not only does not socialize with me but has gone out of his way to harm me in the past.
This leaves me somewhat ambivalent regarding sibling relationships and certainly any celebration of siblings in general.
Today is such a celebration. Siblings Day, aka "National" Siblings Day is some what of a newer holiday honoring the relationships of siblings. It recurs each tenth of April but lacks the national status of a Father's Day or Mother's Day.
It is my understanding that many states issue proclamations recognizing Sibligs Day and that the movement in the United States is becoming one of International scope with obvservations now spreading to Australia and India.