I don't go to rallies or protests much myself. Well, ever, really. I don't like crowds. It's not that I'm afraid of them, or even all that uncomfortable being in one. I just don't like them that much. The only time you can get me into a crowd is if there is a major sporting event that I want to see.
But none of that makes me unquallified to tell you what you should bring to protest an anti-war protest, should you happen to want to go to one.
Of course, just because I'm qualified to tell you doesn't mean that I'm capable of coming up with any ideas.
The only thing that I can think of is the rumor that like the French, most Hippies can be rendered powerless with the use of personal hygene products. So when faced with an anti-war protest, I recomend bringing soap. Lots and lots of soap. And deoderant.