Summoner's Rift Mirror
Don't know if it's already been brought up before, but it popped up in my head so I wanted to mention it. It would probably be most fitting as an April Fools thing, but I think having a mirrored Summoner's Rift would be interesting. All monsters in left side are on right side, bases are in top left and bottom right. You get really used to the jungle, but I feel having it mirrored would disorient players when they try and travel through it and look for specific camps, and make for some funny and awkward plays.