I was there for Mardis Gras for the last 3 years and yes, they do have a celebration/parade thing at Pleasure Island. They throw beads and dress up. I do remember that I wasn't too impressed as it wasn't as good as it is here in Lafayette. It was crowded with a lot of Louisiana people as the kids are out of school at that time. If I remember correctly, the celebrations are the entire weekend before Mardis Gras straight to the Tuesday.
Lisa