I assume Gent would be amazing at any time of year but we visited over the last weekend of their Gentse Feesten which was a blast. We really stumbled which reminded me that some of the best travel adventures are completely unplanned. What a fun outdoor festival.
It is an amazingly little city with so much history. Also, don't miss the Adoration of the Mystic Lamb which is in the Saint Bavo Cathedral while visiting. There are many other great highlights.