I tried everything I could think of and finally ended up bombing the hell out of the house. The first kind I got didn't seem to accomplish much of anything (aside from the wretched smell and icky film) but another brand helped and blowing a second dose of that onto everything seems to have subdued the fleas enough to keep the cats (and me) from acting so crazy.

If next year is half as fleaful as this, I intend to call in a professional instead of messing with a series of pointless do-it-myself attempts.