The Proving Grounds
http://static.planetminecraft.com/files/resource_media/screenshot/1238/proving-grounds_3625725.jpg
Riot, can I suggest that you retool the old Proving Grounds map, and re-release it if you decide to add Butcher's Bridge as a random map that can sometimes exist. The Proving Grounds wasn't a bad map, but the room for a new map on a new aram queue was good. I'm not saying I'm upset it's gone, just that if we're including ARAM maps as a roster that has a chance to show up, why not bring it back but newer?
Maybe re-design it so it looks more like new rift. And has a backdrop instead of just blackness.