MAIN CMIP5 page at PCMDI
A Summary of the CMIP5 Experiment Design (31 Dec 2008, pdf)
CMIP5 standard output specification
Recommended CMIP5 forcing data
NCAR CMIP5 planning and coordination
Excel spreadsheet detailing experiments, responsibility, PEhrs, and data volumes. Plus more. CCSM specific.
CCSM4.0 CMIP5 Century-Time Scale Climate Change Experiments
Other information
CLIVAR WGOMD Committee on CMIP5 Ocean Model Output (Mar 2009, pdf)
Metafor CMIP5 metadata project