This holiday is part of the "Golden Week," a period of several successive national holidays. People commonly take the entire week off and go on vacations. Children's Day is a holiday to celebrate children's well-being and happiness.
The name Children's Day is misleading, though, as this is a day for boys celebrated with carp kites and the traditional Japanese military helmet which represents masculine strength.
In recognition of the national holiday, the JCCCNC in SF presents the annual Children's Day Festival in Japantown on May 2.