How about a "Suggestion Box"-style Q&A, featuring a "potluck" full of subscriber-submitted questions that don't necessarily fall neatly into a specific topical niche or category? We, as Medium members, would have a calendar-based time limit during which to submit our questions ahead of Medium Day -- and the staff/team would pre-select an hour's worth of these "potluck"-style questions of ours, which they'll read & answer during the live event.