There are so many different ways to "run" professional development for teachers. This Poster Session gave some great ideas.
See the slides here and a visual here.
The ones that I like the most include "lightning learning", which allows lots of teachers to share in almost like a "speed geeking" type session. This is also one that I think could be done easily.
I'd like to see more of "PD in your PJs" and get teachers watching webinars and learning from those across the globe that are sharing. I have learned so much from different webinars I've attended through ISTE, ASCD, EdWeb, etc - and so many of them are free!
The idea of a "summer innovation stipend" intrigues me. Of course, there is a lot that goes in to finding the budget for that, but giving teachers time and incentive to explore something they are interested in and passionate about can lead to great growth.
All of the other ones are great as well, but those are the three that intrigue me the most. Check them all out on the slides here and the visual here. There are more details of each type of PD on the pages here.
There are also some good ideas on teacher PD from another poster called "Effective PD for a Changing Culture" here.