Weevil Story!
Last summer we started finding weevils all over the floor in one of our rooms. They started spreading and getting worse. We couldn't figure out the source of the infestation. All my brewing grain in the basement was fine, as was all the flour and dry goods in the pantry. The weird part was there was a noticeable concentration in one area of the house and they would spread from there.
We were going to get our house resided soon due to some woodpecker damage to the existing siding, and that's when it dawned on me the damage was on the outside of the same wall where we saw the heaviest concentration inside. I went outside and looked, and there were weevils on the side of the house. But still, no apparent source. But that's when it dawned on me: I had a compost pile of spent grain in the backyard over the summer-- I typically dispose of it at the town dump but for whatever reason I couldn't so it just stayed out back. It was 30 feet away from this side of the house. I went over and poked around with a rake. It was infested with everything you can imagine... a squirming pile of spent grain and all sorts of critters. And of course, plenty of weevils. I doused the thing with bug spray, buried the entire mass in a 3 foot deep hole, and a couple days later the problem resolved itself.