Brise soleil, or sunbreakers, used to be a popular and effective way of keeping cooler before air conditioning; Like awnings, they were another way of stopping the heat from the sun before it got inside. They could be carefully designed to permit the lower winter sun to enter, and the vertical fins controlled the late afternoon sun in summer. They fell out of favour when it became cheaper to run air conditioning instead of paying for all the stuff on the outside of the buildings.
In Ravenna, Italy, Piuarch uses Bris Soliel to great effect. They tell Designboom:
Defining the external appearance, a modular facade with a grid of rectangles in diverse sizes and orientations are layered over the glass curtain wall. The brise soleil's adjustable solar filters change the exterior while the shadows generated by the continuous movement of the sun adds a dynamic character while framing activity occurring inside.
You can see how the angled wall on the right of the window lets in morning sun, but the perpendicular wall to the left stops the afternoon sun.
At night, it glows. Really, if more architects would start thinking of these as architectural features as well as simply solar control, we might actually save energy and get more interesting architecture. More at Designboom