Empty saltine cracker box with the bottom removed and paper bags make delicious hidey houses. No cracker box? That's ok, other boxes work just as well! Crumpled up newspaper balls are fun for guinea pigs to roll around and chew on. They love to play in paper sacks too! You can take those round oatmeal containers and remove the bottom for a cool tunnel of fun!
There are many other things you can find around the kitchen that your guinea pigs will enjoy. Girl scout cookie boxes I've seen make great houses with a little piggy entrance cut in the front. Take a look around at cardboard pieces you'll be recycling and see if they might be useful for your guinea pig. Just remember to be careful that you don't use anything that the guinea pig could crawl in and become stuck or get their head stuck in. If you're not sure, cut it down the side before placing in the cage so it can't become dangerous.
My guinea pigs love playing with all of the above when they are available. I leave them in the cage for about a week or two, and when they look well worn, out they go. Since it isn't something they constantly have available, they always find it new and exciting. Look around, be creative, and have fun!
If you have extra fleece laying around the house, there are also many things you can do with that for your guinea pigs. Here are a few "no sew" things I've done that are popular with my 3 guinea pigs:
This first one I call "the corner curtains" takes an estimated 5 minutes to create. I took a strip of fabric and used safety pins to secure it to the top of the cubes like a strap. Then I took a long, thin fleece fabric (fleece scarf) and folded it in a "V" shape. I hooked the top of the V to the corner of the cubes and let the strips hang down to each side like curtains over the strap that is pinned up. Chewy enjoying this one in the below picture.
The third thing I made, a corner hideaway, became so popular I made a second one. I took an extra cube grid and used zipties to secure it to the corner of the cage. Then I took a piece of fleece and cut it twice the length of a grid (approximately 28" if I remember right) and made the width slightly less than the height of my cage. You want it to not be the full height of your cage so the fringes don't drag on the ground - this keeps it clean longer. Once I had the piece of fleece cut, I laid it out on the floor and cut fringes up to 1.5" from the top that were about the same size to fit within each square grid within the cube. Then I pulled the fringes through all the outer holdes on the cube I ziptied to the corner of the cage:
You can see I put a piece of fleece on the ground, so they have something comfy to lay on. I also put a piece of fleece on top of this cube, to create the dark hideaway. This is very simple, low maintenance since it doesn't get dirty fast, and they love it!
Thanks for coming here to read this, and I hope this has helped you create a fun an interesting habitat for your guinea pigs!