Playpens!

My boys outdoor yard is like 25' by 30' its made out of 24" high chicken wire and stakes. They have an old cathouse in it to run and hide in if they get spooked and they also had a few pvcpipe tunnels but my brother ran over them with the tractor when I had them out to clean so they dont have them any more . Here is a pic if you wanna see it (broken link removed)
you cant see the cathouse or 2 other tunnels in the pic but its the general idea. So you say yours is a 2x4 maybe you could instead of putting it ina square/rectangle put in it a circle it would make it a lot bigger! some times i'll give my boys a pile of leaves to run and hide in and play in but be carefull if you do this so there's no leaves that couldve blown from a neighbors yard who had chemicals on there grass that couldve been on the leaves so if you dont live out in the country or on a large property where you are sure there are not any leaves from anyone elses trees who couldve put chemicals on it dont do this.

Wow! You're pen is huge! *jealous..lol*

I am using the cubes, and cannot seem to get them in a circle...

Are they connected with the plastic connectors or with cable ties? You get much more flexibility as to shape with the cable ties - we used to keep about twenty grids cable-tied together for the boys' floortime.

I cheated a bit!! lol I went to a baby store and invested in a play pen that way, the pen I got meant that if I brought extra sections I could make it bigger, each section is made out of strong, plastic and looks rather like the cubes that you use to make a C&C cage. All 3 girls enjoy playing in it, and the best thing for me is that I can use it outside or inside.

I use spare grids zip-tied (loosely) together. Right now it is 7 grids x 4 grids but I just took down my loft so I will add the extra grids to the play pen.

https://s8.photobucket.com/albums/a30/Lady_Buell/Piggies/?action=view&current=101_0025-1.flv

Since I have a dog and three cats, I have had to get pretty creative with making a safe playpen for the piggies. I use three small animal pans hooked together for one big play area in the middle of the living room. Then I take a big tarp and cover the whole thing, attaching the tarp with bungee cords. On the inner perimeter of the cage I line some large concrete blocks so the pen cannot be pushed inward by my dog and retains it's shape. This is very stable so that even if the cats jump onto the top of the pen, they just sit on the tarp and can't get inside. I stayed in the room and watched the dog and cats try every possible way to get in the cage, and they couldn't even get a single paw in there! Now that I know it's safe I've let them stay in there for several days at a time while I clean their huge cage.

Even if you don't have a dog or cat to worry about, I highly recommend covering part of the pen with a blanket or tarp during floor time. The piggies feel much more safe and they will use the space better. My piggies feel so comfortable with the tarp over them that they will sleep out in the open in the middle of the pen with no worries!