When I got home I discovered that Andres had accidentally given away what was going to be the bottom part of my worm bin (to the other guy from Freecycle who came to pick up some stuff), so I went out and got a new one, plus some herbs and assorted other Gardening Stuff. Then I came home, cleaned the rat cage, potted the herbs, and set the worms up in their lovely new habitat of torn paper bags, miscellaneous stems, used rat litter, bits of dirt, and lots of mint. I gave them a nasty dried-out bit of pita bread for their first meal, so they'll have some choice between that and mint and used rat food.
For reference, the household is currently:
Two humans (Andres and me); two rats (Echo and Calliope); a small handful of worms of assorted sizes; an Aleppo pine (Sparky); a very small blue spruce (Bruce); a "Sweet 100" cherry tomato plant; a large rosemary; a scrawny little basil or three; some parsley; a philodendron (Phil); and an aloe.
If all goes well, the worms should increase in number fairly quickly, and we'll most likely be getting two or three new rats next month, after we're back from our trip and these guys are off antibiotics.
 In the If I Keep Living in the Same Place More Than a Year This Will Probably Happen Again Department: Said guy was the guy we met at the picnic tenacious_snail helped host last summer who said the remarkably inappropriate thing about andres_s_p_b's hair. Unfortunately, we got the hey-don't-I-know-you-from-somewhere dance resolved with "oh yes you were at the picnic" before I'd placed which person at the picnic he was. I'm not sure whether he remembered andres_s_p_b or not, but he continues the wildly inappropriate streak.