Due to popular demand here is a video with voiceover describing the capstan line winder.
There's no wind, and its dark outside, so I did the recording in my basement in one take. Therefore no real kite :)
Next time I'll get my shoulder out of the way.
I already have an Idea(tm) about how to automatically prevent the dangerous slack that happens on winding out. Look for follow up on my blog http://hackingonkitebits.blogspot.com/ where how this thing works is already described.