"Co-op vs. AI mode is now available on the European servers for preliminary testing!
The time has come for you and your allies to face off against the fiercest AI to hit the Fields of Justice so far. They’re hungry for battle against human foes and you can hone your skills, try new tactics, and feel the flames of Annie Bot first hand by joining AI matchmaking!" 
You can play Co-op vs. AI mode on Summoner's Rift on 2 difficulties: beginner and intermediate.
P.S.: My first blogpost :)