My wife was making up a bunch of bow socks, thought we'd document it as a build-along for those of you who haven't tried making them. Bow socks are cheap, easy, and quick to make; and do a good job of protecting your hand-made weaponry.
First you need some material. I snagged this camo blanket from the bargain bin at WallyWorld for four bucks and change. At 72" x 90", it's big enough to make a pile of these things. Old blankets, fleece throws, etc. all work well and can be found cheap at yard sales, or stolen for free from your wife's closet.
Fleece fabric can usually be found fairly cheap at fabric shops. As long as it's a few inches longer than your bow, you're in business.
Now cut out your piece the size you want it. She cut these about 72" long by 8" wide, seems to be a good all-around size. A static recurve might need a bit wider one, but these dimensions will work with most bows. Just mark the width from the edge in several places and connect the dots.
When you get it cut out, fold it in half, inside out, and pin it together to hold it in position while you're sewing it.