I feel the bottom of mine and when I'm able to depress it just a bit, I take a SHARP knife and hack off the top and the bottom, then cut down the sides, not being TOO careful to get all the little brown dimples out. Then cut a thick column of pineapple, so that it goes almost to the outside edge of the core... Then I work my way around and cut off columns and cut into pieces. When I'm doing the small piece cutting is when I get rid of the small pieces of the otuside that made it in there. It probably takes me about 3-4 minutes to cut it up.
Or if you're feeling ambitious and have a nice fruit salad, you can slice it in half vertically if it's a good looking one

and cut out the flesh/core carefully and use that as a "boat" for chicken salad or something. It takes me longer to do that, but boy, it sure looks pretty

HUGE, though! I end up hacking the pieces up when I do that, and using them in the salad. It's kinda hard to get to the bottom of the flesh inside the fruit, if that makes any sense.