In the past I've been asked to do the same thing for teachers here in China. What I've found that works very well and that they seemed to appreciate was simply to write some realistic dialogues. I included some margin notes and in some cases explanations in paranthesis that explained the phrasal verbs, slang and idioms. Of course you'll have to model the language first and then have them take turns reading the material outloud.

Keep it simple - a two party dialogue is fine, but make it realistic, not textbook style. Spend some time before beginning on checking for understanding of the vocabulary. When you first model the dialouge, remember that you're an actor, not just a teacher, but start out slowly - after the first two or so readings, you can then model it at a normal pace.

Also, remember that you're dealing with adults; therefore, involve them in the process even more than you would your regular students. It may help to ask them during your first meeting what kinds of dialogues they would find interesting. It's also a good idea to spend a few minutes during that first meeting talking about your own feelings about teaching EFL and discussing as well the aspects of your training that have led you to the approaches you use in your regular classes and the method you would like to use with them.

Above all, keep it casual and remember that they are your colleagues. Before each session, allow ample time for small talk followed by a question and answer session. Hopefully you'll be able to arrange the seating in such a way that it's not like you in the front of the class being the lecturer while they are confined to their desks like dutiful little school children.

The first time I did what you're about to do, was quite interesting and memorable. I was asked to teach about 15 teachers at a middle school for a three hour session each week.I was fairly new at the school, so of course I hadn't had the opportunity to interact with the Chinese English teachers. Naturally, I was a little nervous. But I was well prepared and fortunately well dressed. I say fortunately because as I walked into the room, I was struck with the realization that I was going to be videotaped. So there I was doing my thing while being filmed and photographed. A few days later the video was shown on the local tv station. Well, it all turned out ok and luckily I became friends with several of the teachers. It actually made my stay there more enjoyable than it may have been otherwise.

Well, hope this helps Liz. Good luck and have fun!