At least this one is at a time people can make it.
If any one in the San Antonio are is free on April 15 between 6PM and 8PM, it's at Raymond Russel park just north of the Rim on I-10W (just below The Dominion).
There's a chance that Glenn Beck may show up, too.
I'm going to try to attend, depending on work and how I feel that day since it'll ad another 20 minutes to my commute.
H/T to JD