I masked out half of my eyebrow using the old gluestick and concealer trick. If you aren't familiar with it, it's exactly as it sounds. You just rub a gluestick really hard onto your eyebrow and then put a really opaque concealer over it. Don't waste your money on pro eyebrow masking products, all professional makeup artists use a gluestick. The photoshopping done above makes it look like I've shaved that half completely off, but even without photoshopping, it still looks pretty good.
To illustrate the point, here's a picture of my work at a makeup class I took some time ago. This girl had thick eyebrows that weren't suitable for the cyber look I wanted. On the right (kind of cropped off) you can see the big load of FAIL that the pro eyebrow masking product was. I don't remember the brand, but it cost a small fortune. On the finished eye, you can see the gluestick masking with drugstore makeup on top. If I had better makeup, it would be hidden completely. But for a smoky club, it's good enough. Gluestick wins by a long shot
Do any of you mask your eyebrows or do you shave/pluck them off?