Windfest. Community Boating, By the Hatch Shell, Charles River Esplanade. Boston. 10:00 a.m. to 5:30 p.m. Learn a new challenging fun sport- windsurfing! Classes start every 30 minutes. All equipment supplied but be prepared to get wet! You must wear sneakers or rubber booties to go on a windsurfer! They, and you will get soaked. Bring a clothing change. $10.00 to non-members, Free for CBI Members and all Juniors up to the age of 16. (617) 523-1038. www.sailcbi.org