I sailed once with only my driver's license (which had my married name) and my birth certificate (which had, obviously, my maiden name) without a problem.
Of course a passport is the way to go, but you probably don't have time.
Carnival Elation March 11
Carnival Imagination Sept 07
Carniival Sensation Dec 06
RCI Sovereign of the Seas Sept 06
Carnival Miracle Sept 05
Carnival Glory Sept 04
Carnival Fantasy Jan 04