Brace yourself for the memes. Facebook founder Mark Zuckerberg posted a Fourth of July video on Instagram that showed him trying to balance on a hydrofoil surfboard while holding an American flag to John Denver’s “Take Me Home, Country Roads.” Zuckerberg has posted several hydrofoil photos in recent weeks, including one of a custom board that depicts him slathered in white sunscreen—a nod to a photo of him last summer that sparked a meme-fest.