Penny, Raj, Howard, Leonard and Sheldon are finally back.

And as the much-anticipated series six of The Big Bang Theory airs tonight at 8:00pm on E4, we've decided to remind ourselves of where we left them...

The end of series five saw Howard and Bernadette finally tie the knot. After his space flight was rescheduled (and a terrified Howard tried desperately and unsuccessfully to get out of going) the duo decided to get hitched before he left the earth's atmosphere. After a failed attempt to wed at city hall, all five friends got ordained on the internet so that they could perform the marriage together. 

Leonard and Penny are kind of back together but things already aren't running smoothly. After their first night back together, Leonard 'accidentally' proposed in bed, which didn't go down well with Penny. The pair are still dating, but the path ahead might be rocky...

While the future's uncertain for Penny and Leonard, things are on the up for Amy and Sheldon. Sneaky Amy has used spaghetti with little hot dogs to make Sheldon's feelings for her deepen - he even held her hand during the final episode of series five - so it's anyone's guess where their relationship will go next...

And let's not forgot Howard's venture into space... In the final moments of series five a petrified Wolowitz was hurtling away from the earth - screaming incoherently - while the rest of the gang - all holding hands - watched the rocket launch.

So... where will series six take the gang?

Will newlywed Howard have adapted to life in space or be a terrified as ever? What will happen to Penny and Leonard's fragile relationship in the aftermath of that misjudged bedroom proposal? Is Sheldon ready to take his relationship with Amy to the next level? And will poor Raj ever get a girlfriend? 

What do you think? Share your Big Bang theories in the comments below...