Season 6

Season 6 is the upcoming season of The Big Bang Theory. This season is set to premiere on Thursday, September 27th, 2012 and end in May 2013, while taping will begin somewhere in August. All of the seven regular actors on the show have also been confirmed to return to their respective roles.

Storylines
The Big Bang Theory's co-creator, executive producer, and writer, Bill Prady has revealed several plots for the upcoming season.
 * When the season premieres, not everyone will be in California. This is likely referring to Howard still being in space. In fact, Howard could be in space for the first few episodes of the season.
 * Howard and Bernadette's living arrangement will be resolved.
 * Mrs Rostenkowski, Bernadette's mother, will be introduced.
 * Leonard and Penny will continue to have issues in their relationship, regarding the contradictions of what they want out of the relationship. They will still each be at different places in the relationship.
 * Raj will struggle being the only single guy in the group, especially since Howard is married.
 * Sheldon will essentially remain the same, regardless of how his relationship with Amy progresses.
 * Mary Cooper (Sheldon's mother) and Dr. Beverly Hofstadter (Leonard's mother) will meet, causing a mother envy.
 * Mary Cooper may meet Amy's mother as well, although it will just be mentioned by Sheldon and Amy, and not be shown on the show.
 * Raj's love life will be explored.
 * There is not going to be any wedding in the season.
 * Sheldon will continue to be pushed by Amy regarding the progress in their relationship.
 * According to Executive Producer,Steven Molaro, despite being in space, Howard's issues will continue to plague him (especially regarding his living arrangement now that he is married).

Reference

 * Season 6 spoilers by MUNIZ
 * Spoilers from E! Online
 * Spoilers from Gather.com
 * Spoilers from CarterMatt.com