All pet rats need some play time out of the cage. They need a safe place to explore and time to spend bonding with you. Because our homes frequently contain unsafe items (eg, live electrical cords) and things that a rat might destroy (wooden furniture) and because many do not want rat pee soaking into their carpeting and furniture upholstery, it is important to have a designated rat-safe play area.
Many people use their bed for out-time. If you throw an old comforter or blanket on top, you can protect your mattress and bedding from pee and allow your rats free range of the bed, throwing the blanket in the wash as needed. Another option is the bathroom. Bathrooms usually are not carpeted and usually do not have items plugged in near the floor where the rats would be able to chew on a cord. They can be easily closed off so the rats cannot escape and are pretty rat safe as long as you keep the toilet lid down.
We currently have a play pen set up in a corner of our basement, where the rats can run around and explore and we can sit with them on an old couch that is covered with a sofa cover and then a flannel sheet - both of which can be removed and washed fairly easily. The floor of the play area is covered with old throw rugs that my mom was going to throw away until I absconded with them.
The play pen is surrounded by plywood walls, 2 feet high. Our rats cannot jump this high, so it is secure as long as none of the taller toys get too close to the wall. The rats can jump onto the sofa if they want, but will not jump from the sofa arms/back to the floor. However, we must be present to supervise them, just in case. We do not leave the rats loose in the play area unsupervised.
If we should need to leave them (to answer the phone or the door or for some other reason), we also have our Martin's Play Pen set up on a children's table inside the play area. We can easily move the rats into the Martin's Play Pen and secure the door and they will be safe unsupervised.
We have a variety of toys for the play area that we change around periodically to keep free range time stimulating and interesting. Some of our favorite play area toys are Imaginext toys that my boys outgrew. We have an Imaginext castle and also an Imaginext Gorilla Mountain. The rats love to climb these toys and go through the doors and openings. They can be opened into different shapes, to make new configurations, and sometimes lying them on their side makes them new and exciting. We also have a variety of huts and boxes and a handful of Marshall ferret toys (octopus, alligator, pirate ship, noah's ark, and elephant) that come and go. In addition to these things, we like to use the Super Pet Ferre-Trail tubes (they used to sell these in a large set for a reasonable price, but now only sell them by the piece or two and are more expensive). In the play area, we can build more complicated tunnel mazes than would fit comfortably in a cage setting. We also have a Hagen's Living World Teach 'n Treat puzzle where the rats can learn to move puzzle pieces to find treats.
Both the Martin's Play Pen and our play area have their own litter boxes, and the Martin's has a water bottle in case the rats get thirsty. We have a television set up by the play area, so the kids can watch television while the rats are out. If the kids stay entertained while the rats are out, the rats get more out time.
This play area is only temporary. I have a bird room downstairs but only have a handful of finches left. This spring, we will be moving the finches out and into an aviary and doing a thorough clean and redesign of the room. The rats will then be getting this space as a rat room. It should be fun to have a whole room to dedicate to the rats that will be safe for them to explore for as long as they like. It will hopefully be a space that is fun for both rats and people, so the family will be encouraged to spend a lot of time there with the rats.