Seeing as how others have been adding their ideas, why not, I'll jump in.
Right now, my idea is a game based on some kind of tunneling species, most of the monsters in the game will be the same species as the player. Have been going between the easy way out (dwarves) or something alien. Still not sure.
Basic story will be that the colony you live in is heavily corrupt, and a low class ____ such as yourself is basically a slave for digging new tunnels. One day you are found goofing off with friends, and as punishment your friends are killed in front of you and you're exiled to the surface. The surface isn't safe, so you quickly tunnel back down with a plan to get revenge.
The game will be very classic, with most the major roguelike features. I may end up using an 8x8 tileset instead of pure ASCII, but we'll see. The main unique feature will be a simple crafting system, similar to the old "Survival Kids" game for gameboy. You can try mixing multiple items, if you're successful, you have a new item, if not, the game just says you couldn't figure out what to do. The weapons and armor will be very primitive, such as a rock attached to a stick for a hammer, a sharp rock on a long stick for a spear, etc.
Will be my first time developing under a time constraint, so we'll see how I do
Until then, I'll be studying and working on another simple roguelike, hopefully that will be done before the 7DRL