Generally speaking solids absorb light by converting the EM radiation to lattice vibrations (i.e. heat). The incident light causes electrons in the solid to oscillate, but if there is no way for electrons to dissipate the energy then electrons will simply reradiate the light and the light is reflected.
In metals the transfer of energy from oscillations of the conduction electrons to lattice vibrations is slow, so the light is mostly reflected. By contrast in graphite the light is absorbed by exciting $\pi$ electrons, and the excited orbitals efficiently transfer energy to the bulk so the light is mostly absorbed.
But as dmckee says in his comment, the microscopic physics is reversible. If it's hard for oscillating electrons to transfer energy to bulk lattice vibrations then it's equally hard for those lattice vibrations to transfer energy back to the electrons and hence back out as light. So a shiny metal will be equally bad at absorbing and emitting light.
Similarly, in graphite if coupling of $\pi$ orbitals to lattice vibrations is efficient then energy flows equally fast both ways, and graphite will be equally good at absorbing and emitting light.
In practice black body radiation is a mish mash of all sorts of different mechanisms, and the two cases I've mentioned are just examples. However in all cases when you look in detail at how energy is being transferred you'll find it's a reversible process and the energy flows equally fast in both directions.
In the situation you are describing, the only thing one can take away is that the room you are in is brighter than it would be if the bright room were not there. It does not mean that your room has to be as bright as the bright room, just that your room is brighter than it would be otherwise.
For your new situation with the street lamp:
If you move very far away, but still within sight of the lamp, the light from the lamp or nearby bright objects will still reach your dark room. Your dark room will not be as dark as it was before, even if you judge it to be just as dark using only your eye. Since light is reaching the dark room, that light will cause the room to be a bit brighter.
Using the idea of intensity of light:
An intensity of zero at some point in space means there is no electromagnetic radiation; there is no light. If you stand in a place where the intensity of visible light is actually equal to zero, there is no light there. You won't be able to see anything with your eyes or any other visible light detector.
Make sure you're not confusing zero intensity with a very small intensity. These are very different ideas.
It might help if you take a particle-view of light. Think about the photons leaving the lamp and entering your eye. If they enter your eye, and you move away, they're going to hit the walls of the room instead.
Best Answer
The human eye is only capable of perceiving a very limited range of electromagnetic radiation, with wavelengths ~400-800 nanometer. Objects at low temperatures (room temperature) do not emit an appreciable amount of radiation in this range. The fact that we CAN see objects when it's light is due to reflection. For more info, take a look at this wikipedia page