Sunday Assembly is a church for atheists. It was formed recently by 2 British comedians, who will be present at the event. There are congregations throughout the world, in England, Australia, NY City, etc. "Services" consist of sermon-like speakers, readings, and singing (e.g. “Superstition” by Stevie Wonder). One of the founders stated that one of the church's draws is the fun had by the congregation: “we like to say it’s entertaining but not entertainment.” From The Daily Beast, 21 Sept. 2013, “it has all of the community spirit, engagement, and inspiration of a church without any religious aspects.” (http://www.thedailybeast.com/articles/2013/09/21/sunday-assembly-is-the-hot-new-atheist-church.html)
The location of the service is yet to be determined, because demand has been greater than expected. Free tickets must be procured from Sunday Assembly : https://sundayassemblyla.eventbrite.com/ .
The service will start at 11:00 AM and end at 12:00 PM. IEAA Members will afterwards meet for lunch near the location of the service.
See http://sundayassembly.com/ for general information and use this Meetup Event page for developing specific information and to arrange carpools.