PVC pipes work great. You don't have to worry about sealing the wood and they are easy to clean and work with. I've seen other people using them for their carpets and I use them in my carpets enclosure as well. Just come up with a general plan on how you're going to build your "jungle gym" because even though the pipes are really cheap, all the fittings can add up. As far as fake plants etc craft stores are a whole lot cheaper than buying them from a pet store.