You can contact the 7drl.org webmaster (currently Tom Larsen) using this form. Before you do so, please note: (1) This is a community blog with a large number of contributors. (2) If you want to get in touch with the developers of a particular roguelike, you will need to find their details another way. (3) There are no official organisers of the challenge and this form will not help you contact any organisers – you will need to seek out roguelike communities if you wish to find out more about the process. (4) Your question may already have been answered on the 7DRL RogueBasin page.
But, if you have suggestions or questions that remain, please get in touch! 🙂