Many playpens that you buy usually have a regular mat that they will put in the floor of the playpen so that your child is not sitting on a hard surface. There are mats that are of special colors and different shapes. You can get mats that come in pieces and interlock together so that you can purchase this mat for any size of playpen that you have. You can also find mats that are miniature mattresses. They are not as thick as a regular mattress but they are soft enough to where your child would even willing to take a little nap and be very content.