Researcher's note: I actually haven't watched Code Geass, so please try helping me here

About

Spinzaku is a fan name which is a portmanteau of both spin and Suzaku. It is about an impossible spinning kick performed by a character named Suzaku of the Code Geass anime.

Code Geass is an anime about a Brittanian student named Lelouch aka Zero and his attempt to overthrow Brittania using his given ability to command people.
The person doing the kick is named Suzaku, Lelouch's best friend and rival.
Although the said kick was on many scene, the more exploited scene on Episode 2 of Code Geass R2, where Suzaku tries to attack Zero while avoiding gunshot as seen below.

[[Needs info about who started the posting and remixing and in what forums the videos were posted to, if any.

This also needs information regarding who the first uploader was, on what date they first uploaded the video, and preferably, when the video got most of its views.]]

Spread

Apparently Spinzaku is actually just a forced meme of /a/ that started around April 11, 2008, after Code Geass aired the episode 2. The meme itself got old in 4chan quickly but not before many fans started making different derivatives and variations below

It may have turned old quickly on 4chan but, analyzing to the Google Search Insight, the meme itself lasted for almost the whole year of 2008, rising on its peak on September 2008, then waning on December 2008.

Derivatives and Variations

Images:

Many otaku refers to the Spinzaku as a mixture "Falcon Punch (or kick in this matter)", "Chuck Norris's Roundhose" and "Peter Crouch can do anything" where otakus refer Spinzaku as a very powerful kick. Most of the pictures posted below are Spinzaku and its successful attempt to break stuffs, or else kick an opponent. There is a variation where Lelouch, who is actually just overwhelmed in its original picture, is shooped so that it looks like he is being kicked with the Spinzaku.