Spider in Lunchbag: It Was Terrifying, OK?

This is not exactly on the subject of Stamford, but human distaste for spiders is universal.
Last weekend I couldn't sleep. I went into the kitchen at 5am to get a snack. I washed my apple, got a paper towel to rub off any leftover pesticide, then saw a gigantic spider in my lunch bag right beside the paper towels I had just used. (My lunch bag is a foot tall, so do you see how big this spider is?) I leaped back three feet and crouched down a little.

"Oh my god. OK. OK... how am I going to take care of this." I said that out loud, you know, to calm myself and make myself feel like I was not alone.

I'm not ultra-skittish about spiders, but this one was large enough to scare me. Even worse, it was on a soft surface, so I was unsure I could swiftly
a) smash it, or
b) cover it with a glass and use the "glass and paper" method to remove it from the house.
You can't botch the kill/capture of a large spider, because it would be loose, near your hand.

I stood for a couple of seconds, unable to think of a solution. That's rare for me; I'm usually good at spider removal. I ran and got my camera to document the dilemma. I knew I'd want to share and analyze the situation later.

I took the photo, capped my lens, then looked at the spider again. I stuck my head kind of close for a second, just to get a look at him, because he wasn't a type I'd seen before. No dramatic markings. I pulled back to a safer distance.

Here's how I handled it:

1. Gave the lunch bag a tap to assess his jumpiness. If he had moved, of course I would have screamed, but the tap also might have put him in a more capturable or killable position. The spider didn't move at all.
2. I carefully picked up the lunch bag, prepared to throw it far away from me if he budged. That also would have been accompanied by a scream. The spider didn't move.
3. I quickly carried him to the back door, undid the lock, and threw the bag out into the driveway.

Whew. For the next hour, I swore I felt spiders crawling on my neck.

I still don't feel that good about the situation. What scares the crap out of me is, How did that spider get in here? Are there more as big as he is in my house?