One I've seen was the use of Action Research with journals & portfolios.

Step 1: What do I want to work on?
Teachers think about a problem or difficulty that they have (in relation to teaching, language, atmosphere, planning, etc), a technique or approach that they would like to try out, or a general theory they have about language learning.  

They make note of this in a journal.  They include the problem/approach/theory, why it's important to them, and what they hope to do with/about it.  Then they discuss with a senior member (DoS, Senior Teacher, etc) or a mentor how to approach the research section, and make a few notes on this as well.

Step 2:  Observation.
Teachers discuss with a senior member or mentor on a suitable thing to look for (eg. What approaches to error correction do teachers use that get Ss to repeat the accurate version after the correction?) and to pick or design an observation task to look for this.

They spend several weeks observing other teachers and collecting data and ideas that they can use or draw on in the next step.

Throughout this they add reflections on their observations to their journal.

Step 3:  Practice
Teachers spend several weeks trying out a technique/procedure themself (this could be the one they've been observing, or it could be one to deal with the problem they're working on or to test out the theory they have).  While doing this they complete a self-reflection or self-observation task for each lesson they try it out in.

Similarly, they add reflections on this to their journal.

Step 4: Review & Presentation
Teachers collate all their journal notes, observation task notes, and self-reflection/observation tasks into a portfolio. They read through it all, then prepare a 5-15min presentation for the other teachers who work with them.

They present this during the next academic team meeting or training session.

Other teachers are invited to make comments, and may even set up their own project on a similar theme.

It was quite effective, but only really worked for those teachers who were particularly self-motivated and/or enthusiastic.  They need to be particularly interested in self-development for this to help.  Additionally, some teachers will need more guidance, and a DoS or ST might need to observe during Step 3 to give the Ts outside feedback on how the use of techniques are going.