One professional development which still pops up in my my mind and was effective is the one in which among the activities for discussion included, "Running records."
Before this Continuous Professional Development (CPD), it happened that the teacher training college curriculum had jut been reviewed and then revised, this included the English course. Running records was a new concept for lecturers in Languages and Literacy department. A number of lecturers were facing difficulties to teach student teachers this concept when dealing with Fluency as a component of reading.
Then, two members of staff had finished their study in Masters of Education in Early grade and volunteered to train other members on how to use running records as an assessment tool. After the CPD, I became knowledgeable and skilled in using the tool and at the same time in assisting my student-teacher how to use running records. Professional development really gives an opportunity for teacher to examine their classroom practices.