From Mario Fan Games Galaxy Wiki

THE VOID was a forum revealed to MFGGers on April 1, 2009. It had archaic topic creation icons, a purple motif and a music embed. Very soon after its revelation, it grew to consume the entire forum.

Earlier, at the end of the Life on MFGG event, the Casual Conversation Castle was capsulized by Evil Space Techokami for use in a superweapon. Something went wrong in the capsulization process, however, and a strange purple vortex appeared within the CCC, drawing a selected group of Casual Members into THE VOID with no way of escape.

Eventually, THE VOID revealed itself to the public eye, and members could enter THE VOID and interact with its unlucky prisoners. Unfortunately, it didn't end there. With time, the entirety of the forum, save the MFGG section, was sucked into THE VOID, quickly followed by the MFGG section itself.

Thankfully, at 7:54 PM, THE VOID abruptly disappeared, and the missing forums returned as if nothing had happened. The Void seems to have vanished completely, but one can never be too sure.