Named for the big park in its heart, Powderhorn is best known for the annual rite of spring that unfolds on its streets: the May Day Parade and Ceremony, under the direction of the neighborhood's venerable Heart of the Beast Theater. This spectacularly colorful grassroots spectacle, with its gigantic puppet-floats and ragtag marching bands, honors the offbeat essence of the neighborhood, which is full of immigrants, social innovators, young dreamers, and veteran activists.