Open Sans

Open Sans is a sans-serif font created in 2011 by Steve Matteson, available from Google Fonts.

Open Sans is designed with an upright stress, open forms and a neutral, yet friendly appearance. It was optimized for print, web, and mobile interfaces, and has excellent legibility characteristics in its letterforms.

It comes in 10 different variants (light, 300italic, regular, italic, semi-bold, 600italic, bold, 700italic, extra-bold, 800italic).