I pretend to be a health nut 3-5 times a day...at meal time, so I love this idea. The guys at life factory saw a need with associated consumer demand. They designed a product around it, found investment and brought it to market.
http://www.lifefactory.com/What is it? A simple glass bottle with a silicone case to increase impact resistance. Zero plastic means zero BPA's (cancer causing, synthetic estrogens) to leak into the water. There are still plenty of simple ideas out there that will sell quite well.
P.S. I have no affiliation with this product, owners, etc.