I'm still working on these, but it's going well.
Last year we instituted an in-house staff development where in-house people presented training before school. I lead several last year -- one on behavior (because the principal was leading and he wanted someone else to do it), and one on technology.
The technology one drove me nuts, because I'd prepare something, people would show and claim they new the subject and sign in.
This year I changed the technology strand drastically. Instead of 6 weeks of a topic, now I do mini-ones. I also make them shorter, starting at 8:15 and ended at 8:40-8:45, but of course you're welcome to stay and continue playing or come back later in the day for extra help.
Today was the most successful. I advertised last Friday late -- next time I'll do a second advertisement then, I've already done the advertisement this week. I had 5 show up. They were all engaged, and two were not technology teachers. Also gave me time to "sell" the server. Something just instituted.
Next week I'm doing Flckr and have invited people to bring an digital camera with a USB cable. Since it's election day I thought I would go a little fun, and people do use Flckr for educational purposes. It is probably blocked by the district but I'll see if I can't get something done in the meantime.
Some actually approached me and asked me for an Excel session, so what I think I'll do is overview how I use Excel (not much), and give them the links to the tutorials I make my kids use.