I think we solved the Case of the Phantom Aroma. Noodles mentioned that the odor was starting to smell more like a sewer than decaying meat. I checked the drain pipe that was running down from the kitchen sink and discovered a bunch of rust at one of the joints. In fact, my poking at the rust with a screwdriver seemed to increase the aroma. (great...) So this morning we called our friends at Southwest Plumbing and by the time I left for work, they were replacing pipes. So hopefully we'll be able to enjoy our basement once again. Well, Noodles and the kids anyway. I'll be working overtime to pay for the plumbing bill. sigh....