This brilliant trailer belongs to a total-conversion mod for Half-Life 2 Ep 2, called CANVAS, and it looks intriguing to say the least. The player controls a psychic girl named Milena and her little stuffed teddy Borden, whom might as well be a furry Chucky. Utilizing an interesting gameplay mechanic making use of color combinations to represent psychic abilities (if I have that right), CANVAS is a 3D puzzle game which has players entering various paintings to solve some kind of dark mystery. So, like I said, crazy.
That, and the developers clearly have excellent taste in music. That there is "Fantasy" by The Xx, whom are an awesome band. Finally, do yourself a favor and check out their website here, because it was designed by a genius.