I could have gotten out.
This would be a solid plan of attack, assuming that the guy in charge would not modify the environment to prevent it (which he didn't do once in the movie).
Step 1: A room to room sweep to destroy all the cameras an microphones. I realise he said not to bother, but there is plenty of time and it would be a good group task to build a bond among the people. Who knows what would happen once this is achieved. This isn't an neccesary step but should be conisdered as it would ruin the point for Big Brother.
Step 2: Collect the lighter, all the curtains and the booze. Start a huge fire in one corner of the house. This would possibly expose an escape route and at least would give you an idea of the building's structure.
Step 3: If that doesn't work I'd attempt to figure out the air exchange system. There has to be some way that the air is moving in and out of the building. The smoke from the fire would give you a good idea. Other options in this area include finding the electrical wiring or water pipes as well as exploring the insides of the food drop off point. These are all possible weaknesses in the building and a good place to start the long digging job.
Step 4: Digging options include the corrosive power of the exposed wiring from one of the lights, improvised axes and maybe even urine. Keep in mind that you will be digging away at an already existing hole in the structure left by the stuff from step 3 (the wiring, pipes, air ducts).
There you have it. With a little patience and team work you could burn, rip and smash your way out.