Oh Mason jars, is there NOTHING you can't do? Okay, you weren't the most portable "on the go" type beverage holder. Until now. Let's hear it for the Cuppow Mason Jar Sippin' Lid!
I just had to post the copy from Think Geek's page, because it's just too perfect:
The humble mason jar has been around since 1858. Always popular among the home canning crowd and "down home" restaurants, it's starting to make a comeback thanks to (of all things!) Pinterest. There you'll find mason jars used in chandeliers, home organizing, wedding decor (it is Pinterest, after all), in addition to storage for make-ahead meals and beverages.
Cuppow's simple design will make it the only travel mug you'll ever need. Just take a handy dandy canning jar: heat-resistant, BPA-free (cuz it's glass!), cheap, durable, and tight-sealing. Unscrew it, pour in your beverage, and replace the inner seal with Cuppow before screwing the lid on tight. You now have a simple, eco-friendly alternative to leaky and ugly travel mugs. Now you just need to hit Pinterest for some juicing recipes…
And it's just $7.99 on Think Geek right now.