Another good thing you could use is one of those "picnic" tablecloths... probably works the same as the shower curtain. I found some at Big Lots for a really cheap price...

We have two ex pens and use tarps to cover the wooden floor.
Works great and is durable.

We have a heavy duty one (grey) upstairs where she sleeps and a blue multi-purpose one downstairs where we have her sometimes when we watch tv.

Here is a picture of our x pen set up. I got really tired of belly bands and am attempting to train my little guys once and for all. As you can see it is on carpet and I have a shower curtain liner under it. The liner is bigger so they couldn't get to edges if they wanted to chew. The pad covered 2 liter is for Sugar since he lifts his leg. I got the idea form someone here and it works great.

that 2liter idea is great! at walmart, they have heavy duty clear vinyl on rolls back in the fabric section.... i bought 2 yards and paid $7.

I use a plastic computer chair mat. I bought it at Office Max and it works fantastic!! She can''t chew it and my carpet is 100% protected.

When Lacey was a puppy my husband set up a "playpen" like enclosure out of an ex pen.

Basically he used the ex pen for the sides, putting it into a square and clamping the sides that came together, making it a large square enclosure, of course still open at the top and bottom.

The he took several (I think it was either 4 or 6) PVC pipes, a couple of inches longer than the width of the pen and cut(sawed) a slit in the bottom of each one at each end so it would hook over the bottom rail of the wire of the pen. He then placed those PVC pipes in the "bottom" part of the pen, about 4 inches off the ground, to make railings for the floor of pen to sit on.

He then cut a piece of pegboard to exactly fit the bottom of the pen and placed it on top of the PVC "rails".

This raised the floor of the pen off the ground so she would not be in drafts and would be up off the carpet.

On top of the pegboard we kept several layers of newspaper, changed frequently, of course!

I hope I explained this so people can understand it! I thought it was such a brilliant solution.

Lacey stayed in this pen whenever we couldn't be with her.

We had had several people borrow this or make one themselves and all have been pleased with the idea.

i have carpet under morgan's ex-pen. at first i had a shower curtain underneath it but she decided it tasted goo and ripped a hole in the middle. she didn't get to any side of the curtain and start from there, she ate straight down and tore it up. So now i have a plastic carpet runner underneath it. its easy to clean and its thick enough so she can't eat it.