Here's the narrative background:

Here's how I mechanically achieved this:

1. I created a chart of every room in the fortress
2. I purchased a X"xY" pad of 1" Graph Paper (which is useful for ANY pre-drawn maps)
3. I drew 15-20 rooms for the fortress on this graph paper. I cut out all the rooms and laminated them to be able to draw on them.

My Postmortem: 

• The nature of this structure makes the dungeon feel really big. It could be 100 rooms for all the players know. But you might only have 10 rooms.
• If the party is split, they may not be able to find each other again. I think of this as a feature, not a bug. Having a party split in this way would add quite a bit of drama to the situation. Sadly my player's party didn't split. The DM may have to intervene to get them back together if things are going poorly. 
• Eventually someone will stand at a door opening and closing it until someone interesting happens or they find the room they're looking for.
• Because it's not a traditional dungeon where the players can see every unopened door, the party needs really clear directions to know they've achieved their goal. Otherwise they're likely to get a bit lost. 

Random dungeons can be fun, but you need to be wary of doors. You could have the door spawn once the door is open, but not change when it's closed.

I use a lot of hallways or portals in dungeons like that. This way there is a constraint on your results. Another tool is one-way doors on timers.

I once even had the room rotate and or flip based on the door that they entered.

I would emphasize that it was created by a group of wizards. Maybe theme some of the rooms or traps off of the schools of magic, and maybe give some similarly themed magic items. Maybe add some scholarly rooms (maybe an observatory or library) and some arcane enemies (maybe an Allip, Arcanaloth, or Lich) 

You could potentially throw in some portals and magically changing bridges/stairs to capitalize on the ever-changing layout of the place.

This could also lead to some interesting traps. Place two connecting portals on either end of a sloped hallway, and drop a boulder into the hall. >:)

Quote from ErikDewhurst >>

Hey all,
I'm a relatively new DM, but what I lack in experience, I over compensate for with creativity and excessive effort.
I wanted to share a technique I tried couple months ago that work well for me. It's probably not original, but hopefully it's helpful to discuss.

Here's the narrative background:

A guild of uber-powerful wizards created a Fortress many hundreds of years ago. When they created it, they imbued it with the power to confuse invaders or trespassers. Each door within the fortress would only open to a predictable room if opened with the right word. Otherwise, those traveling through the fortress would be presented with a maze of rooms. The party has uncovered this abandoned fortress and is on a quest to retrieve spell books of the dead guild members. The party was unaware of the fortress's powers.

Here's how I mechanically achieved this:

1. I created a chart of every room in the fortress
2. I purchased a X"xY" pad of 1" Graph Paper (which is useful for ANY pre-drawn maps)
3. I drew 15-20 rooms for the fortress on this graph paper. I cut out all the rooms and laminated them to be able to draw on them.

During the game, when a player opened a door inside the fortress, the player would roll 1d100. This number would correspond to an entry on the room chart, and I'd pull out the room and put it down.

Once a door closed and reopen, the player would have to roll another 1d100. With the pre-drawn rooms, I could quickly and easily pick one up, and put another down.

This mechanism worked quite well in practice. There were a few things I noticed when running this...

My Postmortem: 

• The nature of this structure makes the dungeon feel really big. It could be 100 rooms for all the players know. But you might only have 10 rooms.
• If the party is split, they may not be able to find each other again. I think of this as a feature, not a bug. Having a party split in this way would add quite a bit of drama to the situation. Sadly my player's party didn't split. The DM may have to intervene to get them back together if things are going poorly. 
• Eventually someone will stand at a door opening and closing it until someone interesting happens or they find the room they're looking for.
• Because it's not a traditional dungeon where the players can see every unopened door, the party needs really clear directions to know they've achieved their goal. Otherwise they're likely to get a bit lost. 

Thoughts?
Suggestions?
Others who've done it before?

 Just as an aside wondering if your a developer (your feature not a bug comment :) ) 

Anyway this is a really good idea my question is why did you get the players to roll?