In summer, Kermesses are organized in many cities, festive events with lots of activities for children, carousels, duck fishing, bumper cars, etc.
Flea markets: take place everywhere throughout the year, allows you to buy items at a lower price (http://www.brocantes.be/fr/agenda/province/Toute_la_Belgique/Tous_les_evenements)
For more information on culture visit:
French-speaking community: http://www.culture.be/
Flemish community: https://cjsm.be/cultuur/