Today is the birthday of Ganesh’s brother Skanda (otherwise known as Kartikeya). There are big Hindu temple festivals everywhere. It is very colorful!
According to Wikipedia, regional differences dictate the order of their births. In North India, Skanda is generally said to be the elder brother while in the South, Ganesha is considered the first born and may reflect historical tensions between the respective sects.
Stories relate episodes of sibling rivalry between Ganesha and Skanda.
Once there was a competition between Ganesha and Skanda to see who could circumambulate the three worlds faster and hence win the fruit of knowledge.
Skanda went off on a journey to cover the three worlds while Ganesha simply circumambulated his parents. When asked why he did so, he answered that his parents Shiva and Parvati constituted the three worlds and was thus given the fruit of knowledge.