Her name is Yolandi visser. She's a South African rapper/singer (and occasional model) and she's part of a musical project/group called Die Antwoord.
I thought she was just kinda' strange looking at first but the more i saw of her i find her really hot and i'm a bit obsessed with her now.
Check out some Die Antwoord videos on Youtube. They're definitely different to say the least!

Ive always wondered.. who is that girl in your sig?