If you've got a sewing machine that's just collecting dust, either because you've upgraded to a newer model or you just don't sew anymore, you can easily repurpose it into a scroll saw for cutting wood with precise, controlled movements.
Whether you're just making wooden decorations or something a bit more useful, a scroll saw can give you way more control over smaller movements than a large saw. In order to do this mod, you'll need to take apart your machine, replace the needle with a blade, and probably tweak a few parts of the machine to accomodate it (like the baseplate). Lots of the materials you'll need (besides the saw blade) you'll be able to get from the machine itself, but you will probably need some epoxy on hand, as well as a dremel to cut into the baseplate (although if you don't have access to one, you could probably use a drill). Hit the link for more detailed instructions, complete with lots of close up pictures to help you along the way.
From Sewing Machine to Scroll Saw, a Christmas Tale [Instructables]