The Mark bookmark just won the Red Dot Award for best design concept in 2007 so it may be available soon. It's a bookmark embedded with FOLEDs (flexible organic light emitting diodes) so that you can read in the dark by setting it on your book. The brightness level can be controlled, and the units use very little energy. I think it's a great idea. I've been reading with a flashlight for years now. Not because my girlfriend cares if I have a lamp on (she gets no say anyways), but because I can't stand seeing the beast out of the corner of my eye when I'm trying to read. She's ugly folks.
Midnight Bookworms Rejoice [yankodesign]