There are often crowds of nutcases in Union Square, screaming against the war. The crowds are college punks, badly aging hippies, and mental patients out for a walk. I doubt this will get any media attention.
I'll probably just stop by tomorrow after work and laugh at the Lefties. The problem with a counterdemonstration is that it's more of a traffic island than a park plus many of the demonstrators are seriously psycho.
I'm not familiar at all with NYC but figured you guys would want to know.