Funny you should ask Jamie as I am twisting up another feather light for myself. You wouldn't happen to be JC2 would you? Anyway, the pen cap clip, bobby pin, double bent safety pin, screwdriver, bent screwdriver, bent picture hook are all ok tensioners. Pen clip and bobby pin being the best. I have heard of people using everything from nail heads to straightened out key rings. If you want something better there are many ways to make them with wiper inserts and street sweeper bristle. Here are a couple of different wrenches...
and from a different angle
HERE Sorry for the somewhat questionalbe picture quality.
These are all made from wiper inserts, the ones I happened to have in my pocket when I rolled in here, but they are variations on the rigid, twist, double twist, flat, loop, double loop, and top of the keyway kinds. They are only limited by the shapes you have use for. I carry the small loop on my keychain for basically everything. There are also step and tapered tension wrenches.
As far as original ideas for different kinds of DIY picks and wrenches maybe look around a little and use the search. I'm sure you will find there are many great ideas floating around.
-Tooly