Wednesday night there will be a number of quiet vigils in preparation for the Prop8 hearings on Thursday. They are calling it the Eve of Justice, and you can find details about vigils across CA (and a few out of state) at the web site. Please go, if you can.
The Eve of Justice web site also has many links to information about the gay marriage issue. And, if you are so inclined, you can watch the hearings live on Thursday. (I won't; I can't bear it.)
If prop 8 is upheld, the courts will no longer have a meaningful role in protecting minority groups or women, since any decision prohibiting discrimination could be reversed by a simple majority vote.
More on the case from the Gay Marriage on Trial article from the LA Times.
Update I have written a DailyKos diary about American beliefs in protecting minority rights in the context of Prop8. To save bandwidth I won't cross post; I encourage you to go read my views there. We can discuss here if you like.