I roasted two batches today, the first one less than half the popper's already small capacity. I think this was too small and I somewhat biffed the roasting; it was difficult to tell when the beans had hit "first crack," kind of the coffee bean equivalent of popcorn starting to pop, and about the start of a "city roast." (There's also a second crack, and at that point you're starting to enter French roast territory, I gather. Beyond that is Italian roast, which seems to be what Starbucks roasts nearly all their beans to.) The next batch I roasted was the popper's full capacity, and it behaved much more like the batch Jonathan made--the notable exception being that it generated a lot of "chaff," basically a wispy skin on the bean being blown off during the roasting process. Evidently decaf beans like the ones Jonathan used have almost no chaff left after the decaffeination process. Both batches I made have a lot of chaff left in the bean, though (in the little crack in the bean), and neither batch looks like the roast was particularly even.
Nonetheless, I had a cup from the first batch after the beans had "rested" about six hours (you're supposed to wait at least four, and preferably a full day), and it was... reasonable. Not as good as fresh-roasted commercial coffees I've had, but not bad for a first try. (The ground coffee from it smells absolutely wonderful, but I'm just not so sure about the taste.) Tomorrow morning I'll probably have another cup just from that first batch, and in the evening try the second.
I'm not sure exactly what all this gives me other than an interesting hobby to pass the time with. But I suppose that's not a bad thing.