Make a playground slide for your pet rats! Cut three long pieces of corrugated cardboard and two thin strips of cardboard to the same length. Assemble the frame of the slide by folding back the bottom edge of each strip of cardboard and taping or gluing the pieces together. Cut two squares of cardboard and tape the squares under each bottom corner of the slide frame. Use tape to attach the two strips of cardboard at an angle along either edge of the slide, cut several dozen small pieces of cardboard and tape or glue the pieces along the ladder side of the slide. Glue several rectangles of cardboard along the bottom of the slide and ladder for additional support, paint or decorate the slide and place a throw pillow or piece of foam at the bottom of the slide.