One of my favorite pre-Sukkot events is our Boys High School sukkah building competition. Instead of judging them on the carpentry or aesthetics, however, we judge them on the near misses - halachik near misses, that is.
The competition begins with the boys spending considerable time learning the intricacies of the laws of sukkah building with their teachers. Then, their challenge is to construct a sukkah (just the walls, not the schach) which looks like it would not be permissible for a variety of reasons, but, in fact, uses various halachik provisions to ensure that it is.
Below you can see their handy-work as well as a bit of the spontaneous Sukkot spirit which erupted from one of the groups.