A battery-powered, clip-on LED gooseneck lamp has saved my butt on many a darkened stage. Throws just enough illumination for charts without drawing too much attention.
I played a show on a fairly dark stage a couple nights ago, with a set list we redid at the last minute. I really found myself wishing I had a light like this and/or a sharpie pen for thicker lines, I jotted the lists down in black ballpoint which was very hard to read on stage.
