Will the US Supreme Court be willing to take on a case that would potentially overturn a Californian ruling in favour of same-sex marriage? If not, provision for same-sex marriage stands as law in California. If so, this will be a very important and legally complex case, in addition to its obvious social importance.
(My views on same-sex marriage can be found in Freedom of Religion and the Secular State, among other places. For a relatively brief discussion of how I see marriage, go here.)