There are many great giveaways going on these days, I'll add more when I come across them.
Diane at painted Lady fingers has partnered with Diamond cosmetics to celebrate her 300 followers and gives away a huge collection of nail polishes (some colours are set, other 8 can be of your choice), check her blog on more details.
Michelle at The Obsessed Beauty Junkie is also having a giveaway, though the prize is yet unknow, as it'll be a surprize. Check it out;)
Bright Lights, Big color are also giving away 3 Zoya polishes of your choice! How cool is that!