On the first Sunday of each month, Mormons typically hold "Fast & Testimony Meeting" during their communion service (called Sacrament Meeting). F&T meeting is an open-mike event: after the opening announcements, prayer, song, and communion, people are free to stand up and "bear their testimony" about anything, with emphasis generally on Jesus, Joseph Smith, Thomas Monson (current church president), the Book of Mormon, etc. (Mormons will be fasting today to try to push God into helping pass Prop 8, just so you know.)
If you're a No on 8 Mormon in California (or in AZ or FL), go to church today and please "bear your testimony" about the harm Prop 8 and similar propositions will cause. I can GUARANTEE that the bulk of testimonies borne today will have to do with "saving marriage" by voting for Prop h8.
I'm really sorry I didn't realize what day it is until now; but as I'm 9 hours ahead of California here in France, hopefully some of you will see this in time to act!