Informal learning offers opportunities for physics – opportunities that I hope the physics education research (PER) community can co-define and engage with. This commentary piece is a personal reflection on this topic. It reflects, and builds on, my Physics Education Research Conference (PERC) 2019 presentation. Grounded in my personal experiences with informal physics education, my PERC presentation asked those present to collectively consider the values, practices, and people they associate with successful informal learning. Attendee comments are presented and discussed in ways that I hope the PER community will identify with and respond to. They suggest myriad opportunities that informal learning offers physics – opportunity to i) engage diverse groups of people in doing physics; ii) for physicists as a community; iii) to advance the field.