In Southern Ontario, if I go to a session, usually in a pub, I expect it to be almost all, if not all, instrumental music, mostly Irish trad, but some English, Scottish, Welsh and Canadian tunes creep in at times. Fiddles, flutes, mandolins, concertinas, accordions, bouzoukis, sometimes a guitar or bodhran seem to be the most common instruments. The tunes are usually played in unison and if a tune is completely new to you, you will either sit out or try to play very quietly.

An open mic is usually one person/duo or small group at a time and everyone waits their turn.

A sing-around, I'm not so familiar with, but it's obviously mostly vocal music.