Yes. We survived. Three potty accidents resulting in two extra loads of laundry (after I had carefully arranged it so I would NOT have to do laundry). Four dirty diapers. One falling off a chair. Assorted emotional trauma. Unwittingly swapped sippy cups. Parents two hours later than initially forecast. But no one got sick or suffered any permanent emotional or physical scars, so it was a success. And none of the accidents were on the couch.
Most of the activities on the list below were well-received. The craft was fun; not only are open-ended art projects more nurturing of creativity, they're a whole lot less work than the kind that have an actual goal. The Bible story was heard by at least some, and everyone loved making their slings go 'round and 'round. (Indeed, one little girl wanted to do nothing but listen to me sing for most of the time. I got rather hoarse.) Jumping on the carpet squares was also very popular, even though only one of the children could technically jump.
The most popular activity, of course, was one of which I never would have thought and probably would have rendered impossible had I had the foresight to predict it. It was climbing in and out of D2's play yard (dubbed the "OK Corrall"), and driving it all around the living room. So much for the instructions that say it is suitable for children from 6 to 42 months. (Or perhaps they just leave open the question, "Suitable for what?" It certainly kept them entertained, even if not contained.
In conclusion, I would like to remark that I have now put "opening a home daycare" somewhere on my list of desired professions below "providing janitorial service for junior high bathrooms." And I fully intend to take advantage of the two evenings' worth of free babysitting I've been promised in return.