I often explore abandoned buildings for fun, profit and inspiration:
However, these days to get a unique pitch of inspiration, instead of just breaking into abandoned castles, or doing drugs like those "cool kids" from DARE commercials... I slap some math into Mandelbulb software, render it and mutate the result, until something wacky comes out!
If you have no idea what Mandelbulb is, go here: http://mandelbulb.com/about/
The most interesting thing about Mandelbulb is that the 3d fractals it produces are literally INFINITE - the 3d space spirals on forever, occasionally folding into itself like a mobius loop.
This effect can create great perspective references for "infinite" cities:
Or any kind of sci-fi scene, really:
I use the Navigator window to fly around the render gawking at the odd angles in the perspective/objects.
Often, it provides me with an experience of an environment that exists out of normal space-time where perspective can twist at random, w