A lot of my posts mentioned my cage's inability to hold humidity, despite all of the precautions. It was about 40% in the cool side and 25-30% in the warm side, and that's with half of the top covered with aluminum foil and misting twice a day. So, I decided to buy some sphagnum moss and put it in the aquarium. After roinsing and wringing it, it was still damp enough to bring the humidity up. It spiked at 73% in the warm side, but it gradually went down and settled in at 58% (on the warm side).

Molly (my ball python) wasn't too sure what to think of it at first. She had just gotten done eating a mouse, and I placed the moss in as she was swallowing. She sniffed it and it didn't seem like she liked it at first (she actually jerked away from it once) but she laid on it for a while before going into her hide to digest. This stuff seems to really help; maybe now I can stop worrying about her getting dried out.