...as declared by a radio station here in Seattle. At least last Feb. 7th was. I am guessing they are going to repeat it this year. A full day of Clash Clash related(covers, Strummer, BAD, originals that the Clash covered).
You can stream the station online. It's http://kexp.org. It's a great radio in general. Many archived in studio performances on their site, which is also worth a look.