The Gentse Feesten (Gent Festival) is July 17-26 this year. Depending upon your tastes, this may be something to attend or to avoid: loads of events, some free and some paid (music of all descriptions, theatre, street events--you name it) and lots of people. The official website http://gentsefeesten.gent/ should eventually have an English version, but as for now it's just in Flemish and says that the program will be available from June 10. If you poke around on the web you should be able to find photos and/or the program from 2014 or other years to get an idea of what it's like.