Difficulty: 2 - Simple Trick
Siteswap: 3
Prerequisite Skills: Cascade, Half Shower
Watch Video - WMV - 0.5 MB

A.K.A. - Windmill, Spiral
It's called False Shower because all the balls are going around in a circle, like a shower. But, notice that the throws are from alternating right/left hands, unlike a true shower.
Instructions:
This trick is actually nothing more than a modified half shower. I will walk you through the steps to transform your half shower into the windmill. I like to compare the throws to a simple geometry concept that everyone learned in school... angles. Remember? Acute: less than 90 degrees, Right Angle: 90 degrees, Obtuse: greater than 90 degrees. This angle will describe how you throw the "inside" ball (the ball that goes under the tennis throw) of the half shower.

Acute Angle - Start by juggling a regular half shower. Notice that the "inside" ball is thrown at an acute angle of about 70 degrees.

Right Angle - Then start to make it so that the "inside" ball is going straight up and down, or right angle.
Obtuse Angle - Now, keep changing the angle of the "inside" throw, until it is actually going in the same direction as the "outside" throw, making an obtuse angle of about 110 degrees. To get this "obtuse" throw to work, you will have to make an under-arm throw while your other hand is reaching across your body.
Now you have all the balls going around in the same direction, in a circle. Your hands will have to move pretty fast, because they are throwing from one side of your body, then the other hand is catching the ball on the opposite side, then it quickly carrying it back to the original side, before throwing again. It will take some practice to get it looking smooth, especially the "obtuse" thrown ball.
Variations:

You may notice that one hand is always on top of the other. You can change which hand is on top (shown to the right), but I find it easier to keep the "obtuse" throwing hand on the bottom (shown above).

You can also change directions from clockwise to counter-clockwise.