'The Invention of Lying' seems like it was written specifically for Ricky Gervais. In fact, he wrote it himself, so that might be true. Nevertheless, Gervais plays the part of world's first liar as if he actually were the world's first liar.

The story about a society where no one has ever lied is just as funny as you might suspect. When everybody tells each other the truth, everyday happenings like an elevator ride with a neighbour turns into a depressing event, a date becomes even more uncomfortable because you'll be told exactly what the other person thinks about you, and you won't ever have to wonder about getting fired because you'll know when it's being discussed right away. That's exactly what happens to Mark (Ricky Gervais himself in the lead role), who works at a film company and is one of the least popular writers they have. It's not his fault, because who could write an interesting movie about the Black Plague? It also doesn't help that movies are nothing more a man in a chair reading stories to you about historical events. That's because people would believe the world was actually going to end if it was said in a movie. You get the idea.

It comes to the point where Mark is fired and is about to be evicted from his apartment because he can't pay the rent. But this is where the fun starts because those events lead up to world's first lie. And Mark invented it.
Of course, this leads to some hilarious scenes in which Mark tries to tell his friends what happened. Naturally, they don't understand any of it because they assume he is telling the truth, even when he says that he's a German pirate with one arm.
This eventually leads up to a perfectly timed emotional scene where he tells his dying mother that she doesn't have to be afraid of vanishing into the nothingness after she dies, but that she'll go to a wonderful place where you meet all your friends and everyone gets a mansion and as much free ice cream as you can think of.
Word about this gets around and pretty soon he whole world wants to hear about these wonderful stories about what happens after you die. That's when the biggest lie of them all happens, namely, the creation of God. Or, as they call it, the Man in the Sky.
It wouldn't be a decent film though, if there wasn't the obligatory love interest, portrayed by Jennifer Garner. She plays her part as the shallowest girl ever with the greatest of ease. It's all about the best genetic match, status, looks, and money with her, but somehow, through the miracle of Mark's lies and such, they become best friends and she starts to see that there's more to people than just chubby and loser.
In the end she does of course find someone with a better genetic match, but any bright film lover can guess what happens following those events.
Supporting Gervais an Garner is a cast of numerous well-known or at least very recognizable comics such as Jonah Hill (Superbad), Jeffrey Tambor (Hellboy), Rob Lowe (Thank You For Smoking), Edward Norton (Well, duh), Philip Seymour Hoffman (The Boat That Rocked) and SNL comedians Tina Fey and Louis C.K., which make the movie all the more enjoyable to watch.

In the end, 'The Invention of Lying' is a brilliantly written film which parodies the human society and organized religion in a way I personally haven't seen before. This makes it a very refreshing comedy to watch. It's filled with numerous sublime one-liners which will crack you up to no end, but it also touches on a whole other, emotional level. It certainly puts lying for your own good in a whole new light. Actually, it does the same for just speaking your mind. Just go see it. It'll definitely be worth your time.