This is actually a good thread, I'm very glad that others are throwing ideas out there. Others besides just Armok, I mean. No offense to Armok.
Give me a roguelike idea with a very simple base.
in response to the roguelike.
Jelly farming. There are red jellies and blue jellies, when they move onto the same square they explode. You can keep them from getting near each other by smacking them, they are propelled some distance away when you smack them and they have a chance of dividing.
In this same vein, you could make it so it's kind of like a NetHack clone, but centered around pudding farming, and with more DFish construction (like, tunnel out a room, install a door in it, that kind of thing), and probably with a town and a safe level or two to excavate and farm puddings in. The town could have rudimentary things that help out (a food store, a store to sell the pudding products, an equipment store, a store that sells crates to capture live creatures/puddings in, etc), and you could need to go down into the dungeon to get different types of molds, oozes, puddings, and slimes to farm. And you could scale down enemies and traps and all that so it isn't about getting a buff character so much as it's about farming puddings. Like Harvest Moon with horrible little blobs crawling everywhere! You could call it Extreme PuddingFarmer!
Maybe you could feed dwarves to the puddings.
Also, I don't have any advice to offer, but I love that idea, Bricks. You could play Barkley Gaiden if you need basketball related jokes or something like that. There's some cool stuff in there. Making it all about equipment sounds like it'd be a really fun idea, though.