The 9/11 Truth Rally in Lafayette Park, Washington DC on July 23rd, 2005
This was the only 9/11 protest I ever went to, and it WAS definitely fun marching on the Bush White House, demanding 9/11 truth. It was also the only time I saw some 9/11 researchers in person (e.g. Nico Haupt, Morgan Reynolds, Paul Thompson, Webster Tarpley).
The day after the protest, I went to a 9/11 conference at American University and listened to a really interesting workshop presentation on the Pentagon event by Barbara Honegger. My write-ups of her talk are here and here.