This is a very important Mahayana Buddhist text, particularly if you're interested in Zen/Chan. In it Vimalakirti, the perfect example of the Buddhist layman, displays his profound wisdom and wonderworking powers. In order to benefit others Vimalakirti displays symptoms of an illness at which point Lord Buddha requests that one if his disciples go visit him and see how he is faring. It is quite entertaining and enlightening how each one of Buddha's disciples and bodhisattvas present in the assembly refuses to go visit the layman because of some past encounter with him which intimidated some and dumbfounded others. Finally, Manjushri, the Crown Prince of the Dharma, agrees to visit the ill Vimalakirti. It is at this point that the main body of the sutra begins with Vimalakirti teaching about emptiness and most important of all non-duality. If you are a student of the Mahayana and have not read this I highly recommend that you do. It is profound and sublime as only Buddhist scripture can be.
Vimalakirti is not only one of the most popular sutras in Buddhism, but it is also one of the easiest to read, most enlightening and at the same time full of humor. Vimalakirti was a Boddhisattva who decides to pretend he is sick so that others will come to him, learn, and achieve enlightenment. Among those who come along is Sariputra, a disciple of the Buddha, who is treated rather irreverently in the sutra. He just doesn't get anything, and his blindness is used in the sutra as a method for teaching. Thus, when he sees a goddess he asks her why she doesn't get rid of her female form (for a male one, since he thinks that would be better). She answers him by changing herself into a male form and Sariputra into a female form, then she mocks him with his own question. The poor guy is bewildered. She then changes him back and explains how neither male nor female is anything, and thereby helps Sariputra along his way to enlightenment by showing the blindness of his sexism.
The highpoint of the sutra is when all the various boddhisattvas are asked how to understand the non-dual dharma. They spout their wisdom one by one, saying how it is neither this nor that, neither this nor that, etc., until finally it comes to Vimalakirti's turn. At that moment, he says nothing and remains silent. "Ah," says Manjusri, "only when words are overcome can we understand the non-dual dharma."
Well, what can I say. I highly recommend this wonderful sutra. Whether you are a Buddhist or just interested in religious texts, this makes for a great read. If I made it seem just hilarious, it's actually also really deep stuff and it will make you think.