If anyones seen the movie Cube, youl love this map http://www.garrysmod.org/downloads/?a=view&id=58408 Its like 20 rooms all with 1 door per wall, 1 for the floor, and 1 for the roof. Many of the rooms are riged with traps that you cant even see until its to late, your goal of the map is to reach the exit, which i have yet to do without no-clip to see it. A gamemode could be made for it, just a simple task of reaching the end. My favorite room to be traped in is when all the doors close off and are locked and it drops a single pistol into the center, when you pick it up its called the "Suicide Gun" your only option is to use it to shoot yourself, it has the animation of you putting it to your chin and pulling the trigger. I dare you to find your way out without cheating or dieing, and remember "The Boot Is Your Best Friend!"
I is going to try once my really slow internet today lets me download this file at the current '46 minutes 37 seconds remaining' mark -.- Edit: Straight down to 9min now o wait..back to 13. lol.