My daughter loves the soft fuzzy feel of fleece, and was reluctant to give up her fleece footy pj's when they got too small and the temperature got too high. When she wanted to wear the too small pj's on an 80 degree F night, I was only able to talk her out of it by promising to make her a pillow from the pj's. Here is what I did.
This is what the original PJ's looked like.
Step 1: Cut off the Sleeves.
Step 2: Sew a line of stitches perpendicular to the zipper just under where you cut the sleeves off. Make sure the zipper pull is BELOW this stitch line.
Step 3: Stitch another line perpendicular to the zipper just above the crotch.
Step 4: Cut off the sleeve area above the stitch line, and the leg area below the stitch line. Leave a seam allowance. I left about 0.5 inch.
Now you have a pillow case. You can stuff it, find an insert that fits, or use all of the leftovers that you cut off, sew them together into same dimensions as the case and stuff that. I did the later, and ended up with a Frankenstein's monster esque pillow, that worked really well.
There was only a little bit of fabric leftover. I cut these pieces into circles roughly 2 inches wide. I pinched these circles at the middle, then sewed that pinch together.
I sewed these together at the base, then sewed them to the pillow.