Cho'gath Eats the World is the brand new game from Riot this April 1st. So if you like retro gaming, Cho'gath, eating people, destruction, and defeating Teemo, then this is the game for you.
Of course, there's a timer on it, so it will probably be gone once that ends. Play through all cities and beat the game to unlock something special. Play it here.
Oh and Teemo fans need not fret, there's a special feature within for you too.