In the blender vase, combine pineapple, and sugar. Blend until it's liquefied.Strain mixture to get rid of undissolved solids. If you are making it to serve later, do this step, and continue the later steps before serving.
Step 2: Crushing ice
Add lime juice, ice cubes, and rum (if you choose to use it).Blend to crush ice to your preferred consistency. It can be made into smaller ice chunks or slushy.
Step 3: Serving
Serve immediately.If you want to make it before guests arrive, follow the first step, and chill covered for later. Complete steps two and three when it's time to serve it.