What Planet Are YouFrom? is not about the destruction of earth nor about the inane sex comedy a number of reviewers labeled/described it. The film explores the nature of male/female relationship quite well.
Questions like: How do we meet each other? What are the female motives for entering the courtship dance? The female reasons? Why is communication between the sexes so difficult? What is about the birth of a child that can heal the saddest relationships? And on and on.
The film doesn't pretend to offer much in the way of answers to these questions, but that's okay. It is enough that it simply raises them. As a science fiction flick, this is not much of a close encounter picture. But as a human drama packed with laughs, it's quite good.
Near the end of the film, the audience is shown an exterior shot of Gary Shandling's planet for the first time. It is a Metropolis-like setting and is completely gray. This bit of symbolism is akin to the drabness of male existence without female companionship--towering and impressive as an edifice, but cold and colourless and empty as well.