Lady Gaga has a cool wig that's made out of real human hair and fiber optics. She shot a video showing them off and how the wig glows. The inspiration for it comes from the idea of a "Disney Princess going to a rave." Of course.
The fiber optics are attached at the root to the wig's scalp, and can be controlled by Gaga's lighting supervisor whenever she's on stage. [PSFK]