To make one, you need a t-shirt, a pair of scissors, and some time to cut things (like when you are watching a movie).
1. Cut the sleeves and neck band off the shirt.
2. Cut the t-shirt open along one side seam to make a rectangular(ish) piece of fabric.
Note: This is the point where I stitched the arm hole from the other side closed every few inches, but I don't think it is strictly necessary.
3. Fold the top of the rectangle down about an two inches and make one inch cuts every inch.
4. Fold the top of the rectangle down another inch and make one inch cuts between the previous cuts. (See below image)
5. Repeat step 4 until you have reached the bottom of the rectangle.
6. Hang your newly made stuffed animal hammock. I tacked it in three places: right side, left side, center back. (I used thumb tacks, which may or may not be the best idea, but they've held just fine for an entire week now.)7. Put all the stuffed animals in the hammock and watch your three your old try to figure out how to get them all "out of bed". Oh, wait, that part is just for me. Hmmm.
General cutting diagram:
Where to tack: