I've got a group of out-of-the-ordinary people who haven't discovered their potential being used as lab rats. I need to develop a fake town with very few slight hints of it being a scientific testing facility. Any ideas?
Put an electric fence around it. That's completely unexpected. Sarcasm aside, maybe you could make the locals act weird and be split into two distinct groups: the scientists, who are always observing everyone, and the other lab-rat people, who are always acting odd due to experimentation.
A town always gave a sense of security, that's important, give them a fake sense of security, but also the freedom to escape. Well not exactly that, but the idea they have the freedom to escape. The town must not be closed, it must be open, and indeed delivery service from outside must came in to make it look naturally. But overall.... subliminal publicity and messaging, that will make them believe that what they see is what they belive, and also that will prevent them to desire to leave the city.
You know, there're quite a few people around this town that makes me creeped out. Like they're... they're WATCHING us all the time or something. I get your feeling man, I got it too. It was like that movie, the Truman Show. Felt like that. You hit the bullseye. It's what I'm feeling too.
How about limiting the choices of food and drink? In an experiment control is important so it probably wouldn't be good to have 'test subjects' that have extremely different eating habits. Something that you think has no flavor like water, does actually taste different at other places. At least normally. If the limit of food is too obvious then your audience will notice and question why your characters don't but make it subtle enough and it will just add to the feel.
Sensors outside the town -- say, infrared motion detectors. Surveillance equipment, and perhaps an unexplained cluster of antennæ or other comm facilities. The limited diet and drink mentioned above is great idea. You can give indirect support to the idea of a controlled community by slipping the impression of unusual cleanliness into the description. It should also give off the air of being planned -- square intersections, modern facilities, and perhaps a utilitarian vibe to the whole thing.
A legit working military base. Increased security, manned access points, controlled travel... absolutely anything medical can be explained as a result of their proximity to deployed soldiers and their related vaccinations, screenings, and susceptibility to foreign diseases... constant rotations of new soldiers in training exercises at all hours... absolutely nothing is going to seem out of context.
Along with what others have mentioned, information from the "outside world" could be limited or repetitive. Similar to how District Thirteen is portrayed in the Hunger Games: the same newscast replays multiple times a week, or new information isn't coming through.
If the townspeople are actors you could have one of them forget that it is their own birthday. Lets say one of your characters wants to surprise a towns person on their birthday so they discreetly check the persons ID (which is fake) but on the day of their birthday no one in town seems to remember its the persons birthday including the person and their family.
Why would the actors need fictitious birthdays? If I were setting up such a facility I would have the actors play themselves as far as possible, including real names and backstory (except for the bits of backstory about being actors and being recruited for the project). Unless the experimenters are portrayed as incompetent, easily avoidable flaws in the experiment design are going to look like plot holes.
One technique that was used in the Truman Show (and which could be used in completely new and interesting ways) is the use of repetition and looping. The actors in the show always worked from a fairly limited script for their specific roles (such as the twins whose sole function was to push Truman against the wall sign so the sponsor's ad would get its required airtime, or the black family across the street whose sole function was to greet Truman in the morning each day so that Truman would say his signature line "Good afternoon, good evening, and good night!"). Obviously a lab experiment requires specific people to perform specific functions. Somebody has to collect the data from the subjects. Somebody has to administer the stimulus (either physical or psychological). Somebody else (maybe a few somebodies) has to ensure that the subjects don't wander away from their designated places in the experiment, either geographically or psychologically. And all of these people are really working stiffs doing a job of some kind or other...so they are going to do what needs to be done, but they may not always be passionate about their day jobs, and their masks might slip from time to time.
As has been mentioned before, you may want to look at treating your characters as if they were in an actual experiment all of the time. That may mean being overprotective to the point where the people around them are very particular about what the main characters eat, or how they stay fit. The ideal town would also probably be under heavy surveillance and everyone would need to know that the cameras are there (and you can give any given reason for their purpose).
Honestly, do you think we are going to give you the ideas we think are good? I have already thought of something that I will use myself. In fact I'm going to write a short summary right now.
Reinforcing bad writing habits is not helping. Running to others for ideas every time the ideas don't flow like water is a bad writing habit. A real writer sets the idea aside when at an impasse. Trust in your mind's ability to work on it in the background. Meanwhile, work om something else for a while.
