Adobe, the software giant has released a new font family and as it is an open source project you may download it for free. Designed by Paul D. Hunt. Source Sans Pro comes in six weights with their matching italics. Letters a and g come in both double and single story. There is also an alternate I with crossbars and the lower case l has a curved foot for better legibility.
The typeface family was developed to be used in digital environments i.e. computer screens. Nevertheless, it will also work when setting text for print, particularly in booklets and catalogue. There is a much longer post on Adobe’s blog with many more details about this project if you are interested.