I'm a member of BABAM!, the "Boston Area Brigade of Activist Musicians", a loose affiliation of folks across various pre-existing HONK! groups.
In the past I've made up some stretchable tuba covers (pretty good custom site for them, there) that identifies the group I'm marching with - it's a convenient place to put a billboard, even though I don't like how it obscures some of the goofy Seuss-ian beauty of the Sousaphone.
Here's the new design:
I wanted to outline what the acronym stood for without nerdily just writing it out in big block letters. I also wanted to keep a bit of a homespun, lowkey look. My solution was to use a special tool in the iPad program "Sketch Club" that lets you draw with words, so to speak. I had to adjust and paint with " ACTIVIST MUSICIANS BOSTON AREA BRIGADE " so that the lines were more clear, and start with leading spaces because of quirks in the line angle, but overall I'm happy with how it came out.