Herald the official start of summer with a full day of fun at Brookfield Place. On Saturday, families can join Offshore Sailing School at North Cove Marina for a Summer Sailstice special (9am–6pm, $35 per person), offering hourlong sailing lessons on the Hudson. On Sunday, catch performances from special guests during the Bang on a Can Marathon (noon–10pm) before recording your own original tunes. Don't forget to hit up Hudson Eats and Le District for deals on tasty treats. All ages.