Longtime Parent Hacker Jill uses a play tent as a comfortable sleeping space for her kids:
I never realized how useful a toy tent could be with children. Not only is it great fun to set it up on rainy days indoors, but it works great for traveling. We realized that our son could wake up in the middle of the night, look around at familiar (tent) surroundings, and go back to sleep. Anywhere. We now use it when we travel to Grandma's, the beach condo, and even when he needs to sleep in the den to free up a bedroom for visitors. He's always at home in that thing! I love it!