S’mores! Pretty much everyone likes s’mores, and they’re a great excuse to get outside and be social. And to make a cozy fire on an October evening.
Of course, if you also attempt to do this with physicists, the discussion is bound to turn to fluid turbulence and vortices and all of that…
In case you were wondering: there is a version of this which involves watching the fluid flow with lasers, because of course they have another way to play with lasers…