It has already happened in real life. During the famous Spanish Civil War many different groups of Anarchists and Marxists worked to keep Franco's army and the fascists at bay. Most of the parties were anarcho-syndicalists so it was a pure revolution of the working people.
http://www.isreview.org/issues/24/anarchists_spain.shtml
George Orwell actually fought in the conflict with the Partido Obrero de Unificación Marxista (P.O.U.M.) and wrote a great account of the events called, Homage to Catalonia.
Your question though is rather vague and leaves too much open. The events of the Occupy protests were just a precursor to much larger revolts that will come within the next two-three years. Occupy didn't solve the problems but it brought the people together under a common issue that has not been resolved. The same issues still persist and the people want real action this time. The next major demonstration across the nation could easily turn violent, we just need to be ready for the worst. What all Marxists, Anarchists, revolutionaries need to do now is just prepare and make their presence at the new demonstrations. The common working class people don't know much about these ideologies so right now we need to work on educating ourselves so that when the next protests start we can be there to show the working class that we all fight for them.
The problem is that ideas like anarcho-syndicalism and Marxism are so demonized that the common people don't understand that parties like that fight for the interests of the people. We all have a common goal, overthrowing the tyrannical plutocracy. Our current system is rife with corporate shills who would sell the lives of thousands of people just to make their pay checks larger.