I'd never heard of the party before but evidentally it's been around a while & also has ties to Occupy, also to the earlier (circa seattle 1999) anti-globalization movement, ralph nader, etc.
Socialist Alternative (SA) is a socialist political party active in the United States. It identifies itself as "a national organization fighting in our workplaces, communities, and campuses against the exploitation and injustices people face every day. We are community activists fighting against budget cuts in public services; we are union activists fighting for living wage jobs and militant, democratic unions; we are people of all colors speaking out against racism and attacks on immigrants, students organizing against tuition hikes and war, women and men fighting sexism and homophobia."[1]
It is active in over 15 major cities in the United States including New York City, Minneapolis, Boston, Seattle, New Orleans, Madison, Tampa, Philadelphia and Mobile.[1] It publishes a national bi-monthly newspaper called "Justice" along with various local newsletters and internet media outlets. In recent years it has centered its activity around various campaigns including home foreclosures, public education, union rights, public transit, and the Occupy movement.[2][3] It is in political solidarity with the Committee for a Workers' International, an international socialist organization headquartered in London, United Kingdom.
http://en.wikipedia.org/wiki/Socialist_Alternative_%28US%29