A Centrifugal fan generator which can be customized in MakerBot Customizer!
Save one of each object types with your parameters and print.
There are many aspects which you can change in this fan, like blade type, distance from center, size, angle, number, base thickness, hole size and shape, etc. This thing can also make a case for your fan, just choose the last two objects from the "Object" selector.
I truly had fun making and improving this, and hope you will using it!
!UPDATE! - 4/20/2015
Added warp function, which allows you to bend, scale and twist the blades (which are now created using linear_extrude), while completely redesigning the blade generator from a 3D only system to one that uses 2D to 3D extrusion.
Discovered how to use union functions to describe multiple parent objects in difference operations, shortened code considerably.
!UPDATE! - 10/21/2014
Small bugfixes, removed any visible artifacts from the model, and did some code cleanup.