This first meeting will mostly be a bit of a "mixer" where we just gather together and get to know one another. In order to facilitate that process, I'll organize us into small teams and propose some simple "puzzles" that will require a bit of CS knowledge to solve elegantly. After each team presents its solution, I'll propose a few topics for our next meetup and/or solicit volunteers.
For now, I'm tentatively scheduling this first meetup for about one month out from now at Digital Reasoning (where I work and can score us some office space.) If more people signup than we can accommodate or not enough people respond, I'll probably switch the time/location accordingly.