In the United States our right to peaceably assemble is protected by The Constitution. Protests and marches are an incredibly effective way to come together as a group to strengthen a movement, and also to gain recognition from the citizens of the country and planet, as well as the attention of the law makers.
Keeping an updated lists of protests and marches is quite a feat. Here are several websites that keep track of many marches and protests. Feel free to post events that you are excited about on the forum!
RallyList - An event website posting national and state events
Resistance Calendar - A community calend