If you asked 100 people to fill in the following blank, Family-Feud-style, what would be the most popular answer?
“I’ve always wanted to learn ______”
In an informal poll of authors of this blog post, the runaway winner was “a new language.”
It’s pretty easy to get through “ciao” and “auf wiedersehen,” but neither of those are going to get you directions to the nearest gas station when your hovercraft is full of eels. 
Duolingo is an online platform for language learning that’s 100% free. As you learn a new language, you also help to translate the web. You can learn Spanish, French, Italian, Portugese, or German.  [UPDATE 2017: And many, many more!]
We’ve integrated Duolingo with Beeminder so you can give yourself extra motivation to make progress towards learning your new language. Just head to beeminder.com/duolingo after you’ve set up your Duolingo account and enter your Duolingo username. Beeminder will check on your progress every day and make sure you stay on your Yellow Brick Road.