Headlamps are handy for doing things, but they're usually inconvenient to carry. Most are palm-sized or else really not very bright - some have battery packs dangling, and they usually have straps all over. Why not stick your favorite tiny light to the side of your head, for (nearly) free?
Instructions I found. They work pretty well. The "make a washer and sacrifice 2 zip ties" is optional, and only needed if your elastic cord is thick compared to the zip tie head size.
Here's my Quark MiNi AA with this treatment. The MiNi is almost never more than arm's reach away, and this quick addition makes it more useful.
All wrapped up. I tied the same knots they did, with the little pull tab for untying it. That's the part that sticks out; I could take extra time and tuck it in, or just grab the end without making a handle if that bothered me.
Wearing it. I'm not propping it with the camera, honest.
Side view. I don't normally have the elastic so high on the back of my head; I'm not sure what happened really.
Tossing my head to dislodge it - nope. You can see the lanyard quick-release hanging near my ear.
I didn't need a washer to help hold the cord on because my zip tie is huge and the cord I used is small. Make sure that the elastic cord goes through the zip tie on the opposite side from the zip tie head. Also, a black zip tie would look way cooler. This won't be as good a headstrap as a purpose-made one, but you can see from the first picture that it makes no practical change in light size.