Wow, what a great site. Thanks for the info Catalan.
At the site, search for "foto" to find all the photo albums, and also click on "video" on the left. Here's what I learned:
I assumed that the goal of this game was to build the tower higher and higher, until it collapses. But apparently they go to a preset height and that's it, which makes it way safer than I thought. It's also way more organized than the above picture suggests. In fact, I think the above picture is a tower in the process of collapsing. If you look at the guy midway up on the left, his feet don't seem to be supported by anything.
You can see different arrangements and techniques in the photos. For example, compare and contrast:
Between the first two, notice the different hand positions, as well as the central "stabilizing" tower in the middle.
Also, looking at the videos, it's cool to see them scurrying up the tower like ants (in the second video), and then sliding down like it's a fireman's pole (first video).