|Sorry about the picture quality- I'm still learning my new camera|
I used my Day Camp t-shirt for the week before and sewed the sides to narrow it, leaving room for arm holes. Then, I sewed the bottom shut to make a sack. To get the kid into the sack, put him in feet first, through the head hole. Then, pull the sack up, slipping the arms into the holes. Ta-da! A sleeping bag that keeps him from climbing out of his bed! I also love that it's become part of his routine. By the time he gets his diaper changed and gets his sack on, he's ready to sleep!
like this) or you can just get some t-shirts at Goodwill and spend a bit of time on a sewing machine. I hope I've been inspiring (and not too confusing).