The summer heat is quite nasty where I live, and I wanted to give an old desk fan a facelift and renovation. The fan itself was a simple caged desk fan that would plug into the wall. I fashioned a box to hold the fan itself, with a hooded duct to direct the air outward. Mesh screens on the sides of the box act as air inlets. The top of the box is also hinged, and with a turn of a brass knob a small arm flips up to prop it open, allowing even more airflow. I also wired in a potentiometer that when twisted, allows the fan to rotate at varriable speeds, and will turn the blades off and on with a push inward.
The fan works very well, and the many degrees of adjustment on amount of airflow and speed make for an efficent fan with great degrees of fine tuning. I also used this at my place of employment this summer, until I was told that it looked 'too dangerous' (although it is no more dnagerous than any other desk fan; the blades are fully enclosed behind the origonal heavy gague grille), and was told to remove it.