Founder Melanie Hurley had a great idea when she started the earth-friendly company Piggy Paint. With kids spa-themed birthday parties getting more popular every day, Hurley thought it was high time to make some water-based nail polish for kids. From colors such as Clouds of Candy to Mac-n-Cheese Please, Hurley's polishes are as “natural as mud” according to her website.  Polishes run around $3 per and are completely odorless since...