I recently tried out the solo game/dungeon generator How to Host a Dungeon. The results aren't a complete keyed dungeon like you'd get using the tables in the back of the 1st edition DMG. Rather, you get this cool historical overview of the dungeon and a nifty vertical map that can serve as the springboard for level design.
Most of Dungeon Kurazocan was designed by long-gone drow and carved out by their subhuman slave-things. Notable non-drow areas include the scribbly bits bottom-center, which is the home of the Orcs of the Green Flame, and the squares on the righthand side of the map, which started as a dwarf mining colony but was later conquered by a party of evil adventurers. One of the adventurers, a mad wizard, opted not to return to the surface and has instead turned his talents to conquering the dungeon. Apart from the orcs, this wizard's main rival is Althiona the She-Rakshasa, who has many men and monsters under her hypnotic sway.
I haven't a single level mapped or even a lone room keyed, and I already know more about this dungeon than pretty much any other I've designed. How cool is that?