Boys' Day (5th day, 5th month) is an old-custom Japanese festive day to celebrate, well, boys. Not to worry, there was also Girls' Day on March 3rd (3rd day, 3rd month).
In Japan, this was long ago consolidated to 5/5 as "Children's Day" but in Hawaii, as well as in this household of ex-pat Hawaii adults, Boys and Girls' days are still separate, but equal.
All will receive some yummy traditional and and modern treat, because it is after all, a celebration day. 'Grown-up' boy gets mochi (for good luck) and cherry blossom white bread (because he likes it and I never buy white bread). For the boy/children, their favorite Japanese soda candy or rice crackers for *both* kids even though it's officially Boys Day. And Calpico for all.
Typically, they also get a token present. When they were little, it was usually some sort of stuffed animal fish, but now it'll be more like a mechanical pencil or an iTune. Such is the life of modern American Japanese kids...
Whatever your traditions--Happy Boys Day and Happy Cinco de Mayo.
Eat Well. Be Well.