When does summer officially begin? By some calendars, when the city initiates its weekly Bicycle Sunday program, which closes Lake Washington Boulevard to cars from Mt. Baker Beach south to Seward Park. (There are obvious exceptions, including Seafair, per the city Web site). But maybe that moniker, “Bicycle Sundays,” sounds too exclusive, too uptight and sanctimonious. Oh, look at you on your $5,000 carbon-fiber Cervélo, saving the world from global warming! The dirty little secret is that you can also ride your skateboard, push your baby jogger, run with your dog, scoot on your Roller Blades, flaunt your recumbent or unicycle, or just plain old-fashioned walk that lovely stretch of lakeshore without being molested by encroaching SUVs. Bicycle Sundays are open to everyone. But, please, all users should observe the standard etiquette of keeping to the right lane—just like driving. And serious cyclists should also remember they’re not competing in the Tour de France, so give some shy space and a smile to the kids and grannies you’re overtaking at 25 mph. BRIAN MILLER

Sun., Aug. 26, 10 a.m.-6 p.m.; Sun., Sept. 2, 10 a.m.-6 p.m.; Sun., Sept. 23, 10 a.m.-6 p.m., 2012