Owen Sound isn't really a place to come to for nightlife... but if you must, there are a couple of rather dismal bars (as someone else mentioned above).
In the winter around Christmastime, there's a rather impressive display of lights and decorations all along the river (which runs through the center of town - you can't miss it). To the best of my knowledge there are no nightclubs in town, and the only place open really late for a cuppa is Tim Hortons. Most restaurants are closed by ten pm. The boutiques usually close around 8pm if not 6pm.
Someone's always trying to start things like a roller rink or youth club but those all close within the year.
Dress Code: Tee and Jeans.
When 'going out on the town' in Owen Sound, there's not much selection. Basically, you have two places to choose from, Beach Brothers, which has a very small clique following, and The Harb, which has, over the years, become the better of the two bars. Right above The Harb there's Smugglers, a strip club, but its not for the faint of heart or anyone looking for beautiful strippers younger than 50.
The Harb is an alright bar, and its usually packed on Friday and Saturday nights. The Tragically Hip, Blue Rodeo, and even Tom Jones have played there, but beware of the extremely-cautious bouncers (unless you know someone who's friends with one of them). Most Saturday nights a fight breaks out in the street between Harb-goers and Beach Brothers-goers. Most of these idiots are young or from the nearby Meaford Tank Range (army base).
Dress Code: none...could probably get in naked.