It can also depend on the port and passenger demographic, for example non-US pax can delay the whole process if they haven't been cleared prior to arriving in a US controlled port, or nationals from some countries are not permitted to go ashore in other regions.
But for the normal day to day events, Donna's answer has it all.
Last Cruise: Minerva April 2015
Next: Royal Princess August 2015
Then: P&O Oriana October 2015
and : Queen Victoria January 2016
Golden, Grand(2), Caribbean, Sea(4+1 aborted)
Adonia(4+2), Arcadia, Artemis(2), Aurora(5), Azura(2), Britannia, Oceana(3), Oriana(11), Ventura(2), Victoria(5)
QM2(2), QE2(9), QV(6), QE, Caronia(2), Minerva, Minerva II, Fred.Olsen(8), NCL Jade, =X= Eclipse, HAL Ryndam, Aza.Journey