a very cool talk topic would be about UI that encourages casual interaction... like building tools that feel "low stakes".
sort of what casual games are to games, but casual tools and making UI spaces that encourage being creative without obligation...
imo UI has an "atmosphere" and isn't always all about usability... the act of exploring is valuable too
either way, it's an interesting topic and it's fun to analyze these old tools and figure out why they mean what they mean to people.