There are two good windsurfing locations: Lakeview Beach (West Side) and Marina International (East Side). Both feature a grassy rigging area about 80 feet from the launch.
Conditions
Lakeview is shortboard sailable in every direction except directly South.
Northeast: Best. Flat water inside and rollers outside.
Southwest: Rolling smooth surf-sailable waves close to shore
East: There might be wind near the breakwall, but dead on the inside. Sometimes it's worth the schlog out to the winds. Marina International is a good choice when Lakeview gets too rough.
West and North: The breakwall that's west of Marina makes it easier to launch in rough conditions.
From I-90 or Route 2: Take route 58 North. Right turn onto Lakeshore (Route 6). Go East 1 mile to Lakeview.
Marina International is 1 mile further East. Cross Basqule Bridge downtown; left at the first light.
What to do afterwards...
Javkalope Restaurant; accross the parking lot from Marina. Has a patio and a view of the marina and lighthouse.