This isn’t a billboard or formal ad campaign, but the American Humanism Association has been putting up images on Facebook as part of a “Sounds Like Humanism” campaign, in which people said things that could easily be labeled as such even if they didn’t actually use the term.
I posted about the Dalai Lama last month.
These are also a couple from politicians, past and present:
I love this campaign. It’s reminding people that even if they don’t call themselves a Humanist, many of them are pretty damn close to it. You can see future images on the AHA’s Facebook page.