Opening the book…
New people spend their first weeks proving they belong, which means hiding everything about themselves that isn't relevant. Reversing that — putting them in front of the room as the one who knows something — sets their status before the group has decided it for them. It also gives everyone else a fact about the person that isn't a performance metric.
Ten minutes, no slides required, anything genuinely theirs: a card game, how bread proves, a bird you can identify by sound. Ask in advance and privately so they can decline without an audience. Show up and be the most interested person there.
Skip it for anyone who joins mid-crisis, and offer an alternative for people for whom standing up in front of a group is a real cost rather than a mild nerve — a shared write-up does most of the same work. If the group is large enough that this becomes a weekly ritual nobody attends, kill it.