The title of the film tells you exactly what it's about (and it's obviousness makes it even more funny, at least to me). Basically it takes place in a world where everyone tells the truth, but a writer (Ricky Gervais) finds out that he can use it for personal gain.
I'm a big supporter of Gervais. The Office UK and his last stand-up special were awesome. And I even enjoyed one of his recent films, Ghost Town.
I think with him starring AND writing the story about the invention of lying is going to set this up to be a really funny one. Hopefully...