I’m bookmarking both of these sites for later:
This one has links to how to actually get ‘er done
This one makes the tent cover out of an old blanket
This one uses an old twin bedsheet
Both seem pretty simple. All it seems like you need are pieces of wood and a bit of material. I’m not sure if I want to start on it now or wait until we are matched with a second baby. I love the idea of each of them having their own little play area in the back yard.