The DSA is a voluntary, nonprofit educational corporation, organized for the conduct of research and education of the public in the use of dozenal (also called duodecimal or base twelve) in calculations, mathematics, weights and measures, and other branches of pure and applied science.
In this document, DSA board member Timothy Travis (#342) presents some beautiful graphics and commentary regarding his love for dozenals and his ideas for using them. The playing-card back he designed is especially lovely.