The Projects Curated by Curator section on the Front Page shows the five most recent projects that were chosen by the latest curator. A curator selects a project by favoriting it, and is the curator for a week (formerly two weeks). It is updated when a new curator takes over, or the current curator picks new projects. It sometimes takes a little while to update.
This row is currently the 3rd one from the top.
Very rarely, a user will have the same project curated twice.
When the Collab Challenge 2011 results were released, the user Collab-Challenge was chosen as curator and displayed the chosen projects in this row. Instead of the usual learn more link, it was replaced with a see more link to this studio. The same thing happened at the end of each Collab Camp.