"The Guardians of Soreth" is a module presented as a 40cm x 28cm folder built from multiple sheets of paper taped together. Inside are lots of maps, new spells, and cut-up pieces to a literal puzzle.

The front cover..

The back cover, which is pretending to be an "official" module by listing all available commercial modules, just like TSR's module's do.
The 3 modules at the end are custom modules, two of which were the projects of my brothers Imran and Mashuri.
The last "official" module listed, "Lost Tomb of Martek", was published in 1983. So this project was created no earlier than that year.