Our staff at VHS spent the day learning from each other on Monday for a full day in-service. How often do we listen to our teachers and ask them what they want to do for professional development? I am definitely guilty of this in the past. It is so easy to send the staff to a massive PD opportunity than to put something together that is actually worthwhile for EVERYONE. We all have experts on staff, empower them and have them present on something that they would like to try or other staff would like to know about.
In the past we have spent the day at a full day in-service where we cram 300-400 teachers into a gym and learn about the same concept. Most of the time the concept doesn't apply to half of them. Don't get me wrong I believe these full day in-services can be good, but often they are not.
So spend some time talking to your teachers the next time you and your administrative staff plan a PD day. Let loose of the control. It might be the best professional development they have ever received!