The XY Simple Questions, Simple Answers thread is a great place to ask any simple questions you might have relating to the OU metagame. Do not make new threads for questions that could be answered here.
The OU Usage Stats show which Pokémon are used the most in OU on the simulator. The most recent stats are for March 2013.
The OU Viability Ranking thread shows how well every OU-viable Pokémon fares in the OU tier.
The ORAS Metagame Discussion thread is an open platform to discuss any aspects of the current state of the ORAS metagame.
The ORAS OU (no Mega) Ladder thread encourages discussion for the alternative ladder that prohibits the use of Mega Evolutions.
Pokémon of the Week features a different Pokémon each week with the intent of finding the best counters and counter-strategies for it.
The OU Theorymon Project discusses Pokémon that would otherwise be unviable in the ORAS OU metagame to formulate possible alterations that would increase their viability.
The Next Best Thing takes a look at a different Pokémon each week in an attempt to find new and creative sets for it.
The OU Teambuilding project aims to build an effective team for the OU metagame through community submissions and voting.
The Don't Use That, Use This project aims to help new players by creating a list of what not to use and what to use instead.
Lower Tier Threats is a project that aims to compile a list of notable lower tier threats through poster submissions.
The OU Teambuilding Competition gives a two Pokémon core for members to build the best possible teams in order to win in a community vote.