Hey, thanks for the tips, folks.
I have poked around into the idea of making mini-sites; I'm just intimidated by the time involved. I have a lot of things going on at once, all the time.
I have Adsense installed on the sites that are live. It does okay.
My parked domains are at Namedrive.com and Sedo.com. I had all of them at Sedo for a long time; I've recently moved a bunch to Namedrive and can already tell it'll be a better payoff than Sedo.