In re: Marriage Initiative of 2009, District of Columbia Board of Election and Ethics, November 17, 2009 [holding that Washington DC's Jury and Marriage Act, which allows DC to recognize same-sex marriages performed legally in other jurisdictions, could not be challenged by a ballot initiative because overturning the law would violate the DC Human Rights Act].
Reported in JURIST's Paper Chase here. Latest commentary available here. JURIST has more on legal issues surrounding same-sex marriage.