They come indoors all the time, especially at a change of seasons. Suddenly cold-- the come in. No rain and drought-- they come in. Pours with rain-- they come in. The last seems to be the worst invasions, I guess the rain drives them from wherever they've been living all summer.
They only bite if provoked and it's about as bad as a wasp sting. I've known several people including toddlers who were bitten in their sleep, didn't wake up and just had a big red swollen area for a few days. So I guess it can't be that painful. Though I did have a friend who used to feed them water from a teaspoon while they sat on her hand and she was finally bitten and said it hurt. But not as bad as a wasp.
They are called huntsman, in Hawaii they call them cane spiders. They mostly like to be up high on walls so you really have little direct contact unless you decide to catch it.