Just a normal game of league of legends, only difference is that every single champion, item etc. were all brought back to a state before the nerfs, changes etc and the items that were deleted were all brought back.
The map can be the currently updated summoners rift or the crystal scar, twisted treeline, howling abyss or the maps before they were all visually upgraded.
All of this in one special game mode just for the hell of it.
Don't you sometimes wish you could play AP YI, Release Darius, Draven, Jax, Xin zhao etc just that one last time?
Don't you miss force of nature, heart of gold, philosophers stone that you used to have in those item slots?