We always like discovering group runs.  They are a great way to see the city with fellow runners along-side and can introduce you to locals as well.  Running Room is the Canadian equivalent of Fleet Feet--many stores throughout the country.  Toronto has approx. 8 locations and all offer group runs leaving the stores on Wednesdays 6pm and Sundays 830am.  Call the particular location to verify times, distance and routes.  We've provided the address here for one downtown store.