In past years when I have attended Festival dete de Quebec, I have stayed inside the city and just attended activities related to the festival. This year I contacted the Quebec tourism board for ideas of tourist activities outside the city.
One of the activities that immediately jumped out was to visit Sainte-Anne Canyon. Sainte-Anne Canyon is a naturally sensational area right outside of Quebec City. There is a beautiful park with walking trails and a few adventure sports for families who are feeling adventurous that include rock climbing in the waterfalls and a suspension bridge walk.
There is also a new ride that just opened one year ago called Air Canyon where two people sit in a chair and take an exhilarating ride across the canyon. This was a fun activity for anyone who wants a birds-eye view of the canyon.