Lets see now, you separate a dungeon into a large cubic grid(10ftx10ftx10ft), and then from a predefined entrance, you roll for each of the 5 sides to see if they are connected to something. For each adjacent connected cube, feed it(divided into a 5x5x5 grid) into a table of features, with wall sections, trap sections, open sections, and 'interesting terrain' sections, each section going into a table with exact type of section obtained and allowing for overlaps. Then roll to see if a connector is wide open(merging the rooms into a larger room), a door(roll for type of door), or a destructible barrier. Repeat until desired dungeon size is obtained.
Then you do it again with encounter tables....I'm putting way too much thought into this aren't I?