Lil Grotesk is a nice straightforward sans serif font available under the free software SIL Open Font Licence. And this month it is my font of the month.
I found Lil Grotesk on Open Font Library, which is in itself a fantastic project. It brings together a collection of hundreds of free software and open source fonts. And you can embed them Google font style with the snippets provided by the site.
I am a great fan of the nicely cut C and G characters, particularly in upper case. For me the lower case looks a bit wonky, which makes me think that I would be more likely to use the font as a display font in all caps. But I am a stickler for regularity and others may find the slight wobble charming.