9 a.m.: registration for Cardboard boat race at Peconic Riverfront, downtown Riverhead. Sponsored by Riverhead BID, this annual event brings people out to cheer on boats made by families, business owners and other community members. Awards for first, second and third place in a variety of categories. Rubber duck race hosted by the YMCA of East Hampton. Races begin at noon. Free. Information: Diane Tucci, firstname.lastname@example.org, 631-209-4244.