do a search in google using "define mardi gras" and you will come up with a list of definitions for this french phrase that is more commonly referred to as Shrove Tuesday or Fat Tuesday. Mardi Gras refers to the Tuesday that falls just before Ash Wednesday, exactly 46 days before Easter and preludes the penitential season of Lent.
Sinulog is a festival that is kicked off by a nine day novena to the Señor Santo Niño de Cebú of which the start date is dictated by the culminating grand parade on the tenth day of the festival. the parade happens on the 3rd Sunday of January.
This festival in Cebu is relatively new (the Cebu version started early 80's) and does not have the historical roots as some of the other christian festivals that's being celebrated in the country. that hardly matters as the Sinulog is now recognized as the grandest Philippine Fiesta complete with sponsors, concerts, beer, booze, lechon, parties, production numbers, fully booked hotels, massive traffic, drunk foreigners... uh i almost forgot, the novena.
Sinulog commemorates the event when Christianity was embraced by the Cebuanos (and arguably, the country) when the spaniards led by magellan, docked in mactan island and presented the image of the Señor Santo Niño de Cebú to Queen Humamai and Chief (Rajah) Humabon. the chismis goes that humabon had an ill grandson that magellan (or any of the medico in his crew) cured. not satisfied with converting them to christianity, they baptized humamai and humabon as juana and juan and little sick grandson as juan jr. - i suspect they had a hard time pronouncing the original names but that's another story
of course we know the story of how magellan got filleted by lapu lapu, another chieftain in mactan island, when magellan tried to do the same trick. my conspiracy theory is that lapu lapu got pissed when magellan said that thereafter, lapu lapu will be called larry.
so pleez people, stop referring to the Sinulog Parade as a Mardi Gras, in the first place, it is done on a sunday (not a tuesday) and it is not an activity that preludes the lenten season.