Greywulf wrote an interesting article about generating dungeons from Sudoku sheets, so I figured I'd make a dungeon from that system. (The article is here.)
First I need a Sudoku sheet. Google to the rescue! Google finds websudoku.com! That was easy.
I picked an "Evil" Sudoku in order not to clutter the dungeon with too many features. There was a marked decrease in numbers between that and "Easy" (the page's default). Funny thing - an Evil sheet probably tends to give an Evil dungeon, as most doors will be hidden. Less encounters, though.
The rest is just about following the directions in Greywulf's post.
First we get a rather plain setup with large rooms surrounding a central secret room in a spiral-ish pattern (single doors are secret, double doors are plainly visible). Decent architecture! Clearly some evil mastermind is hiding in the central room.
In fact, there aren't many foes in this dungeon. Just a double encounter (overleveled + normal) in the top left room, and the aforementioned mastermind (normal encounter) in the central hideout. If I were doing this seriously, I'd probably move one encounter to another of the big rooms. The perils of too hard Sudoku sheets...
Next is Features. (I'm doing NPC/puzzle last.) According to Greywulf's table, there're rotten bodies in the lower left room (right where the PC:s enter, yay), and a barricade in the top right. I'd definitely move the monsters into the room with the barricade if I was doing this for real.
Traps next. The top left and bottom right rooms have traps. I figure the monsters in the top left room would put alarms on both doors, and the mastermind has probably trapped the visible door into the lower right room because nobody uses that room (or at least not that door - it could be a storage room intended to be reached from the central room).
Treasure is second to last. Well yeah. In D&D4 terms, treasure parcel 2 is in the central hideout, and if the PC:s rifle through the storeroom to the lower right, they'll find parcels 5 and 9. Greywulf suggests using either treasure parcel numbers, or saying that "higher is better". Funny, because the treasure parcels with low numbers are worth more (powerful magic items, as opposed to regular gold coins). Ergo, treasure parcel 2 is pretty yummy.
Finally NPC:s/puzzles. The top right and bottom left room has some. Definitely captives in the top right one, whether there are monsters there or not. The bottom room is harder - maybe the PC:s can perform some forensics on the piles of dead bodies to figure out what awaits them further inside the complex. Or maybe there's a huge symbol shaped like the map - it would look arcane, but after two or three rooms, smart players might figure out that it's a map (and start looking for a way to the center).
The result might need some tweaking, but this is how it turned out, after adding some furniture to the rooms. The bottom left serves as garbage disposal - the monsters in the other rooms eat a lot of meat and need to put the bones somewhere. The top left is elite quarters - spacey and with heating. The top right is an old mausoleum - coffins and whatnot has been layered along the walls and serves as a barricade where it crosses the doors. the lower right room is a storage room, and there is good reason to assume that was its original purpose. The inhabitants never enter through the trapped door (with a pit behind it).
The central room is the laboratory, library and sleeping room of a cunning wizard. He will escape through one of the four secret doors if he is gravely threatened.
That worked out okay. Might need an easier Sudoku if I try again.