Sourdough workshops near boston

Does anyone know of any sourdough workshops in the boston area or any bakeries that are willing to have someone come in and help out/learn? I am looking for day classes or possibly a longer commitment (i.e. 4 Saturdays) I looked on King Arthur's website and they offer one course that interested me but the dates dont line up with my vacation time from work. I am willing to travel some - if it is a day-long or weekend commitment. 

thanks!!