Inspired by an idea from JW of Vlambeer, I built this dungeon generator.
In short it adds a bunch of rooms on top of each other and then moves them randomly around until they don't fit any longer. Usually this makes for some very nice and organic looking scenes. This version also has a bunch of other parameters like wider door ways, interconnectedness, and decoration among others. The example in this thread randomises these parameters but in the code it is fairly easy to set them up to whatever.
I've tried to document it to a degree, so hopefully it can help out if someone wants to dive into my implementation. It should be said though that I primarily wanted to visualise the process and to look nice, not necessarily be the most efficient data structure. ;)
Have fun and let me know if there are any questions!