Marching seems to be in vogue these days. After a week or so of online organizing, it seems likely there will be a March For Science in DC, in the near future. A couple of references include,
http://nymag.com/scienceofus/2017/01/scientists-want-to-march-on-washington-too.html [nymag.com]
https://www.washingtonpost.com/news/speaking-of-science/wp/2017/01/24/are-scientists-going-to-march-on-washington [washingtonpost.com]
One of the links suggested that lab coats would be recommended attire. Although I'm an engineer, I think I have an old white lab coat somewhere...