Lightning talks are super-fast presentations. The maximum length of the presentation is 5 minutes -- they are intended to be low pressure and to not require extensive preparation time. They can be a detailed discussion on a very specific topic, an introduction to a product or technique you are interested in, or even a question you'd like to ask the group.
Anyone is welcome to do a lightning talk at any meeting -- just talk to us at the beginning of the meeting and we'll make sure we schedule you in. You're welcome to use the projector and screen... and someone can probably lend you a laptop if required.
As always if you'd like to do a full 30-45 minute presentation, just contact Jonathan or I... we'll be happy to schedule you.