We have a meeting every two weeks which usually has two short presentations on different topics. We try to target different audiences with the presentations, so both people new to Linux and grizzled veterans can take something home with them.
Guidelines for administrating a meeting can be found here.
We try to keep the powerpoints and videos for each of our past meetings. This way people who can't attend can still catch up on what they missed. Please see the above meeting guidelines for more information.