Alki is a wonderful public place. It has a sandy beach, waterfront trail, restaurants and cafes, views of the Olympics and Seattle, and offers some of the best people watching. Alki has something for almost everyone and is well used public space. And it's the kind of environment that encourages physical activity--walking, biking, skating, dancing, volleyball, swimming, and more.
Ciclovias temporarily close streets and reclaim them for use by people to gather, walk and bicycle. Some Washington communities are holding ciclovia events and you can read a blog post about it.
read a post from the Project for Public Spaces blog about this movement.