If you have a lot and would like to get rid of them at once, you can drop them off at one of the recycling centers (like the DRS Community Center in Satellite Beach) or solid waste facilities. You can find the closest facility to you at https://www.brevardfl.gov/SolidWaste
You can also give them away through Freecycle.org or Space Coast CraigsList, for example. You will be surprised of how many people need cardboard boxes for packing stuff away or store items when they are moving offices and relocating with their families.
Now, if you have kids, you can easily reuse your cardboard boxes. Besides using them in craft projects, like the ones listed at http://www.squidoo.com/fun-with-boxes, you can also do as we do at home: they turn into canvas. In the garage, my daughter has long-lasting fun applying watercolor paint, crayons, markers, stamps, you name it, to lids and broken-down cardboard boxes. Once she is done with them, we may keep some of her art and then place the rest in the recycle bin.
Recycle Brevard!