Labyrinth is a cool store but I think they only specialize in board and card games, and puzzles. Their Instagram bio actually says, "A non-electronic game and puzzle store on Capitol Hill, in Washington, DC. We host tons of gaming events, and love supporting our community," so I doubt they have video game-related events for something like Fortnite. But it is somewhere that a kid may discover fun games and people, and some of those people may happen to also like Fortnite.

Here's their Instagram: https://www.instagram.com/labyrinthdc/?hl=en