Does anyone have any recent info on how that ranking works? We can gain 200 stars a day, and still have never been on the trending page, even within the C++ section, where projects gain ~15/day.

I noticed some odd results when switching from "today" view to "this week" view. Maybe they take into account some hidden parameters like diversity of the audience, time distribution, reputation, or maybe they have an odd definition of "week" like last 7 days vs Sun to Sat. If a project doesn't show up maybe the underlying ranking suspects foul play.