The full slate of challenges is now available in Fortnite: Battle Royale for the 14 Days of Summer event. Many of these have involved new elements found around the map: case in point, one asks you to get a score of 10 or more on a carnival clown board. But what is that, and where do you have to go? In the video guide above, you can see exactly where such a board is located and how you score 10 (or better). [Update: The 14 Days of Summer event ends very soon, but it's not too late to jump into the game and knock out any lingering challenges from it that you haven't yet done. Each challenge offers a specific reward, but if you manage to do all 14, you'll also receive the Smoothie back bling.]
Essentially, your task is to play whack-a-mole with inflated balloons. You can do this by shooting them or (more stealthily) swinging your pickaxe. As each balloon inflates, you'll want to pop it, but beware that the speed at which they come up will increase as you score points. There are different boards around the map where you can do this, but the one seen in the video is more secluded and should thus be safer. It's found east of Paradise Palms and has the bonus of counting toward another 14 Days of Summer challenge, to visit the beach parties.