Namiko wrote:
I know someone who purposely keeps the spiders in his house alive so that they can eat the flies and gnats that come in. 
I do that too, as long as it's not a black widow (I get those in the house sometimes), the spider in the web is live, and the web isn't old and dirty. I had an old family friend that used to do the same thing, but they were on a ranch, so that was considered more socially acceptable.
A few months ago, I walked off the edge of the front porch, and walked into this giant, super sticky, invisible web. It was really hot that night and I didn't have a shirt on so that addede to the sensation. I had something like a panic attack and rushede over to the full length mirror to see if the spider was on me, but it wasn't. I grabbed a flashlight and found a black widow on the ground wher the web had been. I was at about knee level and 6" to my right when I waked through the web. I wasn't the biggest one I've ever seen, but it was still big. I figure the web was roughly triangular and about 8' tall by 7' wide. I was picking bits of spider web out of my hair for a couple of days because it wouldn't wash out very easy.