The Ultimate Chex Quest (TUCQ for short) was started when Mark Quinn (A.K.A. Boingo the Clown) downloaded the Scifience Studios version of Chex Quest. Seeing that it was nothing more than the old Chex Quest packaged together with Doom Legacy and the Scifience logo slapped on it, he decided to make his own 'beefed up' version of Chex Quest.
He started by merging Chex Quest 1 and 2 into a single wad, then moved on to the detailing, where the project is now. After the detailing is completed, he will add more levels to the game to make a full 36 levels.
Originally begun as a mod for Doom Legacy, on November 11, 2007, after months of discussion on the Chex Quest Fan Forums, it was decided that the project would be switched over to another Doom source port, GZDoom, in order to take advantage of features it has which Doom Legacy does not, including 3D model support and higher resolution graphics.
Boingo took down all Chex Quest-related material on his website in 2009, announcing the cessation of work on the mod. However, he put all the material back up on his birthday in 2011. Shortly thereafter, he announced that work on the mod would resume. The first new version of TUCQ since 2005 was uploaded on November 18, 2012. This version was essentially a straight conversion of the mod over to GZDoom with only a little new content, but it did indicate that development on the project would continue.
The current version of TUCQ is Release 6. It was released on January 18, 2014. This version works with GZDooM and functions as an IWAD, meaning no other IWAD is needed.
Earlier version of TUCQ are also available on the website.