Matt Damon is a funny guy, even, it turns out, when talking about a serious subject. In a new YouTube campaign leading up to World Water Day — it’s March 22, so mark it down — Damon shows his silly side. In the first video, posted Tuesday, Damon declares, “I’m going on strike.” Speaking to a roomful of reporters at a mock press conference, Damon says he’s striking to protest the lack of sanitation in developing countries. “Not [striking] from acting, that would be too easy,” he says, “a strike from going to the bathroom.” The reporters appear confused, and then one poses the question that’s on everyone’s mind: “Whaaa?” The YouTube videos, which will feature familiar faces from film and TV, is a collaboration of Google, social-media types, and the nonprofit group Water.org, of which Damon is a cofounder. (The video was shot in Google’s digital production headquarters for YouTube creators, an airplane hangar once owned by Howard Hughes.) We’re told it was Damon’s idea to use humor instead of earnestness, hoping it helps make the videos viral. Consider this: Damon’s funny video with Sarah Silverman has been viewed more than 3.4 million times on YouTube, while his thoughtful vids on behalf of Water.org have been clicked only a few thousand times.