Rules for indoor Flying?
Indoor R/C's recommended guidelines are somewhat similar to the outdoor...
You need a line separating the people from the flying aircraft.
You need adequate room to maneuver the aircraft... how much room is highly dependant on the model. There are some micro R/C planes that can easilly fly in your average living room. Most indoor models need at least a basketball court.
There's a lot of judgement call involved in determining which model can be safely flown at a given indoor site. If a plane is having problems just doing a figure-8 pattern in the spacewithout hitting something or crossing the separation line... it needs to be flown somewhere else.