What about introducing some writing acitivity ideas?
I have a post here somewhere about creating a narrative but it's based on the Mt. Diamonte exchange project
. It basically gives students freedom to create a narrative arround a simple flexible structure and then deals with language and lexical items as they appear. This is supposed to be a much better way for students to acquire language, especially if you can get them to do their negotiations in English. You could then have the participants try to think of different story models they might use with their students in the same manner.
I also have other projects that involve writing in the V-key Pals section. You could discuss how to complete project exchanges using these resources or others like them. They are great motivators.
I use www.eslflow.com
a lot for creating theme lesson units. He has a great collection of links based around themes and you could do a presentation on that. 'Making the most of theme units'