Smashing sportsballer Rocket League [official site] already supports custom levels in an unofficial and slightly fiddly way but will soon officially embrace them. Developers Psyonix have announced plans to add Steam Workshop support, meaning players will simple need to click a button on Steam then fire up the game to play in custom arenas. Who knows what you'll find? A pretty new sportszone, maybe, or an obstacle course, a race, maybe even a nice little Sunday drive through the Cotswolds.
Rocket League doesn't have its own official level editor but players have been tinkering in the Unreal Development Kit to make compatible levels. Sites like Rocket League Mods and others already host maps but the scene's a bit scattered and it's a bit fiddly to play. Steam Workshop support will simplify all this, providing a central place to find maps, easy installation, and an option to play them directly in the game's main menu.
One might expect the exposure and centralisation of the Workshop to encourage more people to make maps, and fancier maps too.
Steam Workshop support will arrive in Rocket League's December update. Psyonix have previously announced that it'll also let people create and share their own training scenarios.