Keep your home dry, and pay special attention to bathrooms and wooded surfaces. There should never be wet stuff or water just lying around the house. Living in a home with things like spores and mold can lead to health problems. If you see black crud forming on your moldings, bleach that stuff up and scrub it. It's nasty and preventable.
I found some mushrooms growing in an old water bottle once. Fungus is really interesting.