Out of nowhere, the newcomer mapper PLA has released the fifth version of his project Dark Tartarus at the ZDoom forums. It's always a great thing if new mappers join the community, bringing in fresh wind and new ideas to resources that have been already used a thousand times in various contexts before. I consider Dark Tartarus to be an exception in design and texture usage and really like what the author came up with. It is planned to be a 43-map project in the end. There is still lots of work left to be done but you can already get a good overview where it is heading. Visit the thread and check the release.